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An Australia-wide consensus was reached on seven core concepts of physiology, one of which was cell-cell communication. Three physiology educators from a "core concepts" Delphi task force "unpacked" this core concept into seven different themes and 60 subthemes. Cell-cell communication, previously unpacked and validated, was modified for an Australian audience to include emerging knowledge and adapted to increase student accessibility. The unpacked hierarchical framework for this core concept was rated by 24 physiology educators from separate Australian universities, using a five-point scale for level of importance for student understanding (ranging from 1 = Essential to 5 = Not Important) and level of difficulty (ranging from 1 = Very Difficult to 5 = Not Difficult). Data were analyzed with the Kruskal-Wallis test with Dunn's multiple comparison test. The seven themes were rated within a narrow range of importance (1.13-2.4), with ratings of Essential or Important, and statistically significant differences between the themes (P < 0.0001, n = 7). The variance for the difficulty rating was higher than for importance, ranging from 2.15 (Difficult) to 3.45 (between Moderately Difficult and Slightly Difficult). Qualitatively, it was suggested that some subthemes were similar and that these could be grouped. However, all themes and subthemes were ranked as Important, validating this framework. Once finalized and adopted across Australian universities, the unpacked core concept for cell-cell communication will enable the generation of tools and resources for physiology educators and improvements in consistency across curricula. [This article was written with Task Force.]

Flipped classroom teaching has been used by many educators to promote active learning in higher education. This andragogy is thought to increase student engagement by making them more accountable for their learning and increase time on task in the classroom. While there are several systematic reviews that point to improved student results, it remains unclear if flipped classrooms have positive learning effects in physiology education. Flipped classroom teaching was introduced in two advanced physiology subjects (advanced neuroscience, "semester 1," and cardiorespiratory and renal physiology, "semester 2"). Changing the mode of content delivery reduced the time students needed to spend listening to lectures by one-third, without sacrificing either learning content or academic standards. Higher pass rates were observed with larger number of students earning distinction and high-distinction grades. Statistically significant improvements in final grades were observed from both subjects ("semester 1": 2017, 49.28 ± 20.16; 2018, 53.29 ± 19.77, t[subscript 268] = 2.058, P = 0.0405; "semester 2": 2017, 58.87 ± 21.19; 2018, 67.91 ± 20.40, t[subscript 111] = 2.306, P = 0.023). Finally, students' perception of their learning experience remained at or above the university benchmarks (median score of [greater than] 80% for all iterations of the subjects). While the most frequent and persistent area that students suggested could be improved was reduction of content, equal numbers of students commented that no improvement in the subjects was required. Despite the generally positive attitude to recorded didactic teaching content, classroom attendance remained very low, and students did not engage with the active learning content. This suggests that more emphasis needs to be placed on promoting class attendance by developing better active learning content.

Bioscience is a foundational unit (subject) of undergraduate allied health degree programs, providing students the scientific basis underpinning their clinical practice. However, despite its significance, bioscience is a difficult academic hurdle for many students to master. The introduction of active learning strategies, including small team-based guided-inquiry learning approaches, has been shown to significantly reduce this hurdle and improve assessment outcomes for the learner. Guided team-based activities can aid in this approach by also building broader skills and capabilities, like teamwork and communication, as well as subject-specific knowledge and skills, thereby positively influencing student assessment outcomes. This paper details the redesign and evaluation of two first-year Bioscience for Paramedics units with the introduction of guided-inquiry learning, as well as other active learning strategies, and assesses their impact on student performance. Results indicate that active learning used within a classroom and in the large lecture theater setting improved students' grades with positive student perception of their learning experience.

Evidence shows that factors contributing to success in physiology education for allied health students at universities include not only their high school achievement and background but also factors such as confidence with their teachers and quality of their learning experience, justifying intensive and continued survey of students' perceptions of their learning experience. Here we report data covering a 3-yr period in a physiology subject that has been redesigned for blended and online presentation. Consistent with previous reports, we show that when we undertook a blended mode of delivery, students demonstrated better grades than traditional modes of teaching; however the absence of didactic teaching in this subject resulted in lower grades overall. Students have very strong positive attitudes to weekly quizzes (80% positive approval) but report ambivalent attitudes to online self-directed learning (61% negative perception), even though they had 2-h weekly facilitated workshops. Overwhelmingly, students who undertook the subject in a self-directed online learning mode requested more face-to-face-teaching (70% of comments). From these data, we suggest that there is a quantifiable benefit to didactic teaching in the blended teaching mode that is not reproduced in online self-directed learning, even when face-to-face guided inquiry-based learning is embedded in the subject.

Self-regulated learning (SRL) encompasses the strategies and behaviours that allow students to transform cognitive abilities into task-specific academic skills. Research in higher education has found a relationship between SRL and academic outcomes. However, whether SRL improves as students gain educational experience in undergraduate science has not been adequately studied. It is also unclear whether traditionally strong predictors of academic performance, such as the Australian Tertiary Admissions Rank (ATAR), and science background, remain strong in the later stages of a science degree. The purpose of this study was to investigate whether SRL changes over time in undergraduate science, and whether SRL, the ATAR, or a student's science background predicted their academic performance. The sample comprised a cohort of agricultural science students (n = 213) from a large Australian University followed longitudinally from 2018 to 2020. Students completed a questionnaire to assess SRL in their first and third years of undergraduate study. They also completed a knowledge survey at the start of first year to assess confidence in scientific material. Analyses revealed that students' SRL increased over the degree, but not over a single semester of first year. Additionally, it was found that students' average semester marks were related to knowledge survey scores, and with students' ATARs, but not with their SRL. These results indicate that the academic aptitudes that contribute to academic success in high school continue to be advantageous through to the end of undergraduate study, but also suggest that students' initial scientific confidence may be particularly important to long-term university success. [ABSTRACT FROM AUTHOR]

An Australia-wide consensus was reached on seven core concepts of physiology, one of which was cell-cell communication. Three physiology educators from a "core concepts" Delphi task force "unpacked" this core concept into seven different themes and 60 subthemes. Cell-cell communication, previously unpacked and validated, was modified for an Australian audience to include emerging knowledge and adapted to increase student accessibility. The unpacked hierarchical framework for this core concept was rated by 24 physiology educators from separate Australian universities, using a five-point scale for level of importance for student understanding (ranging from 1 = Essential to 5 = Not Important) and level of difficulty (ranging from 1 = Very Difficult to 5 = Not Difficult). Data were analyzed with the Kruskal-Wallis test with Dunn's multiple comparison test. The seven themes were rated within a narrow range of importance (1.13-2.4), with ratings of Essential or Important, and statistically significant differences between the themes (P < 0.0001, n = 7). The variance for the difficulty rating was higher than for importance, ranging from 2.15 (Difficult) to 3.45 (between Moderately Difficult and Slightly Difficult). Qualitatively, it was suggested that some subthemes were similar and that these could be grouped. However, all themes and subthemes were ranked as Important, validating this framework. Once finalized and adopted across Australian universities, the unpacked core concept for cell-cell communication will enable the generation of tools and resources for physiology educators and improvements in consistency across curricula. NEW & NOTEWORTHY Seven core concepts, including cell-cell communication, were identified by an Australian Delphi task force of physiology educators. The previously "unpacked" concept was adapted for Australian educators and students to develop a framework with seven themes and 60 subthemes. The framework was successfully validated by the original Delphi panel of educators and will provide a valuable resource for teaching and learning in Australian universities. [ABSTRACT FROM AUTHOR]

The study of human bioscience is viewed as a crucial curriculum in allied health. Nevertheless, bioscience (and particularly physiology) is notoriously difficult for undergraduates, particularly academically disadvantaged students. So endemic are the high failure rates (particularly in nursing) that it has come to be known as "the human bioscience problem." In the present report, we describe the outcomes for individual success in studying first-year human physiology in a subject that emphasises team-based active learning as the major pedagogy for mastering subject learning outcomes. Structural equation modeling was used to develop a model of the impact team learning had on individual performance. Modeling was consistent with the idea that students with similar academic abilities (as determined by tertiary entrance rank) were advantaged (scored higher on individual assessment items) by working in strong teams (teams that scored higher in team-based assessments). Analysis of covariance revealed that students who studied the subject with active learning as the major mode of learning activities outperformed students who studied the subject using the traditional didactic teaching format (lectures and tutorials, P = 0.000). After adjustment for tertiary entrance rank (via analysis of covariance) on two individual tests (the final exam and a late-semester in-class test), individual student grades improved by 8% (95% confidence interval: 6-10%) and 12% (95% confidence interval: 10-14%) when students engaged in team-based active learning. These data quantitatively support the notion that weaker students working in strong teams can overcome their educational disadvantages.

Using a combination of respiratory gas exchange, infrared thermography, and blood glucose (BGL) analysis, we have investigated the impact of Capsicum annuum (C. annuum) fruit powder (475 mg) or caffeine (100 mg) on metabolic activity in a placebo controlled (lactose, 100 mg) double-blinded three-way cross-over-design experiment. Metabolic measurements were made on day 1 and day 7 of supplementation in eight adult male participants (22.2 ± 2 years of age, BMI 23 ± 2 kg/m², x̄± SD). Participants arrived fasted overnight and were fed a high carbohydrate meal (90 g glucose), raising BGL from fasting baseline (4.4 ± 0.3 mmol/L) to peak BGL (8.5 ± 0.3 mmol/L) 45 min after the meal. Participants consumed the supplement 45 min after the meal, and both caffeine and C. annuum fruit powder restored BGL (F (8,178) = 2.2, p = 0.02) to near fasting levels within 15 min of supplementation compared to placebo (120 min). In parallel both supplements increased energy expenditure (F (2, 21) = 175.6, p < 0.001) over the 120-min test period (caffeine = 50.74 ± 2 kcal/kg/min, C. annuum fruit = 50.95 ± 1 kcal/kg/min, placebo = 29.34 ± 1 kcal/kg/min). Both caffeine and C. annuum fruit powder increased supraclavicular fossa temperature (F (2,42) = 32, p < 0.001) on both day 1 and day 7 of testing over the 120-min test period. No statistical difference in core temperature or reference point temperature, mean arterial pressure or heart rate was observed due to supplementation nor was any statistical difference seen between day 1 and day 7 of intervention. This is important for implementing dietary ingredients as potential metabolism increasing supplements. Together the results imply that through dietary supplements such as caffeine and C. annuum, mechanisms for increasing metabolism can be potentially targeted to improve metabolic homeostasis in people. [ABSTRACT FROM AUTHOR]

A reduction of heat loss to the environment through increased cutaneous vasoconstrictor (CVC) sympathetic outflow contributes to elevated body temperature during fever. We determined the role of neurons in the dorsomedial hypothalamus (DMH) in increases in CVC sympathetic tone evoked by [PGE.sub.2] into the preoptic area (POA) in chloralose/urethane-anesthetized rats. The frequency of axonal action potentials of CVC sympathetic ganglion cells recorded from the surface of the tail artery was increased by 1.8 Hz following nanoinjections of bicuculline (50 pmol) into the DMH. [PGE.sub.2] nanoinjection into the POA elicited a similar excitation of tail CVC neurons (+2.1 Hz). Subsequent to [PGE.sub.2] into the POA, muscimol (400 pmol/side) into the DMH did not alter the activity of tail CVC neurons. Inhibition of neurons in the rostral raphe pallidus (rRPa) eliminated the spontaneous discharge of tail CVC neurons but only reduced the [PGE.sub.2]-evoked activity. Residual activity was abolished by subsequent muscimol into the rostral ventrolateral medulla. Transections through the neuraxis caudal to the POA increased the activity of tail CVC neurons, which were sustained through transections caudal to DMH. We conclude that while activation of neurons in the DMH is sufficient to activate tail CVC neurons, it is not necessary for their [PGE.sub.2]-evoked activity. These results support a CVC component of increased core temperature elicited by [PGE.sub.2] in POA that arises from relief of a tonic inhibition from neurons in POA of CVC sympathetic premotor neurons in rRPa and is dependent on the excitation of CVC premotor neurons from a site caudal to DMH. rostral raphe pallidus; thermoregulation; fever; dorsomedial hypothalamus; preoptic hypothalamus

The impact of brown adipose tissue (BAT) metabolism on understanding energy balance in humans is a relatively new and exciting field of research. The pathogenesis of obesity can be largely explained by an imbalance between caloric intake and energy expenditure, but the underlying mechanisms are far more complex. Traditional non-selective sympathetic activators have been used to artificially elevate energy utilization, or suppress appetite, however undesirable side effects are apparent with the use of these pharmacological interventions. Understanding the role of BAT, in relation to human energy homeostasis has the potential to dramatically offset the energy imbalance associated with obesity. This review discusses paradoxical effects of caffeine on peripheral adenosine receptors and the possible role of adenosine in increasing metabolism is highlighted, with consideration to the potential of central rather than peripheral mechanisms for caffeine mediated BAT thermogenesis and energy expenditure. Research on the complex physiology of adipose tissue, the embryonic lineage and function of the different types of adipocytes is summarized. In addition, the effect of BAT on overall human metabolism and the extent of the associated increase in energy expenditure are discussed. The controversy surrounding the primary β-adrenoceptor involved in human BAT activation is examined, and suggestions as to the lack of translational findings from animal to human physiology and human in vitro to in vivo models are provided. This review compares and distinguishes human and rodent BAT effects, thus developing an understanding of human BAT thermogenesis to aid lifestyle interventions targeting obesity and metabolic syndrome. The focus of this review is on the effect of BAT thermogenesis on overall metabolism, and the potential therapeutic effects of caffeine in increasing metabolism via its effects on BAT. [ABSTRACT FROM AUTHOR]

Undergraduate science courses are particularly challenging for students transitioning into university. The departure from supportive high school environments can be difficult for students lacking self-directed and selfmotivated learning skills. Many high-achieving school graduates entering higher education are surprised to discover they are ill-prepared to be accountable for their learning (Stanton et al., 2015). Over the past two decades, there has been a mounting interest in the pedagogical approaches aimed at equipping students with the capabilities of a lifelong learner (Australian Qualifications Framework, 2013; Oliver & Jorre de St Jorre, 2018; Boud & Dochy, 2010). Consequently, research efforts in higher education have attempted to identify the behavioural strategies and motivational states associated with academic success. Self-regulated learning (SRL) is an umbrella term encompassing the independent and self-directed strategies that allow students to recognise and regulate their learning (Dinsmore et al., 2008). In brief, self-regulation is what a lifelong learner does. In science disciplines, much attention has been directed towards curricula that facilitate the development of SRL in students, such that they become aware of, and maintain control over their learning of complex scientific concepts. This study reviews the current theoretical perspectives, methodological approaches, and emerging trends from research on SRL in higher education science. [ABSTRACT FROM AUTHOR]

Functional brown adipose tissue (BAT) was identified in adult humans only in 2007 with the use of fluorodeoxyglucose positron emission tomography imaging. Previous studies have demonstrated a negative correlation between obesity and BAT presence in humans. It is proposed that BAT possesses the capacity to increase metabolism and aid weight loss. In rodents it is well established that BAT is stimulated by the sympathetic nervous system with the interscapular BAT being innervated via branches of intercostal nerves. Whilst there is evidence to suggest that BAT possesses beta-3 adrenoceptors, no studies have identified the specific nerve branch that carries sympathetic innervation to BAT in humans. The aim of this study was to identify and trace the peripheral nerve or nerves that innervate human BAT in the supraclavicular region. The posterior triangle region of the neck of cadaveric specimens were dissected in order to identify any peripheral nerve branches piercing and/or terminating in supraclavicular BAT. A previously undescribed branch of the cervical plexus terminating in a supraclavicular adipose depot was identified in all specimens. This was typically an independent branch of the plexus, from the third cervical spinal nerve, but in one specimen was a branch of the supraclavicular nerve. Histological analysis revealed the supraclavicular adipose depot contained tyrosine hydroxylase immunoreactive structures, which likely represent sympathetic axons. This is the first study that identifies a nerve branch to supraclavicular BAT-like tissue. This finding opens new avenues for the investigation of neural regulation of fat metabolism in humans. [ABSTRACT FROM AUTHOR]

Flipped classroom teaching has been used by many educators to promote active learning in higher education. This andragogy is thought to increase student engagement by making them more accountable for their learning and increase time on task in the classroom. While there are several systematic reviews that point to improved student results, it remains unclear if flipped classrooms have positive learning effects in physiology education. Flipped classroom teaching was introduced in two advanced physiology subjects (advanced neuroscience, semester 1, and cardiorespiratory and renal physiology, semester 2). Changing the mode of content delivery reduced the time students needed to spend listening to lectures by one-third, without sacrificing either learning content or academic standards. Higher pass rates were observed with larger number of students earning distinction and highdistinction grades. Statistically significant improvements in final grades were observed from both subjects (semester 1: 2017, 49.28 20.16; 2018, 53.29 19.77, t268 2.058, P 0.0405; semester 2: 2017, 58.87 21.19; 2018, 67.91 20.40, t111 2.306, P 0.023). Finally, students’ perception of their learning experience remained at or above the university benchmarks (median score of >80% for all iterations of the subjects). While the most frequent and persistent area that students suggested could be improved was reduction of content, equal numbers of students commented that no improvement in the subjects was required. Despite the generally positive attitude to recorded didactic teaching content, classroom attendance remained very low, and students did not engage with the active learning content. This suggest that more emphasis needs to be placed on promoting class attendance by developing better active learning content. [ABSTRACT FROM AUTHOR]

“Only teach me what I need to know!” This commonly heard refrain is often spoken by allied health students while studying preclinical sciences (physiology, anatomy, pharmacology). Here we use a clinical scenario undertaken by second-year Bachelor of Paramedic Practice students of acute coronary syndrome to demonstrate the difference in clinical decision making when using a clinical reasoning approach to treatment rather than relying exclusively on a practice guidelines approach. We hope to demonstrate that understanding basic bioscience concepts, such as the Frank-Starling mechanism and the anatomy and physiology of the autonomic nervous system, are key to providing good clinical care in response to ambiguous patient symptoms. Students who understand these concepts underlying their patient care guideline will make better clinical decisions and better provide quality of care than students who follow the guideline exclusively. We aim this as a practical demonstration of the value of detailed understanding of human bioscience in allied health education. As health care providers transition from “technician” to “practitioner,” the key distinguishing feature of the role is the ability to practice independently, using “best judgment” rather than clinical guidelines (alone). Evidence suggests that complex case management requires detailed bioscience understanding. [ABSTRACT FROM AUTHOR]

Summary: Pharmacological interventions to aid weight loss have historically targeted either appetite suppression or increased metabolic rate. Brown adipose tissue (BAT) possesses the capacity to expend energy in a futile cycle, thus increasing basal metabolic rate. In animal models, oestrogen has been implicated in the regulation of body weight, and it is hypothesized that oestrogen is acting by modulating BAT metabolism. A systematic search was performed, to identify research articles implementing in vivo oestrogen‐related interventions and reporting outcome measures that provide direct or indirect measures of BAT metabolism. Meta‐analyses were conducted where sufficient data were available. The final library of 67 articles were predominantly in rodent models and provided mostly indirect measures of BAT metabolism. Results of this review found that oestrogen's effects on body weight, in rats and possibly mice, are likely facilitated by both metabolic and appetitive mechanisms but are largely only found in ovariectomized models. There is a need for further studies to clarify the potential effects of oestrogen on BAT metabolism in gonad‐intact and castrated male animal models. [ABSTRACT FROM AUTHOR]

Virtual reality (VR) is an interactive experience which immerses the user in a digital environment through a sense of presence. In the context of providing an active learning experience, virtual reality has the potential to improve learning outcomes for biomedical science students as it allows the visualisation of and interaction with digital representations of dynamic objects and complex concepts. Studies in bioscience and medical education have shown mixed results pertaining to the benefits of VR as a learning tool. This review aims to consolidate how VR succeeded or failed in improving learning outcomes, and assesses the issue of VR scalability for the ever-growing cohorts in tertiary bioscience courses. [ABSTRACT FROM AUTHOR]

Bioscience is a foundational unit (subject) of undergraduate allied health degree programs, providing students the scientific basis underpinning their clinical practice. However, despite its significance, bioscience is a difficult academic hurdle for many students to master. The introduction of active learning strategies, including small team-based guidedinquiry learning approaches, has been shown to significantly reduce this hurdle and improve assessment outcomes for the learner. Guided team-based activities can aid in this approach by also building broader skills and capabilities, like teamwork and communication, as well as subject-specific knowledge and skills, thereby positively influencing student assessment outcomes. This paper details the redesign and evaluation of two first-year Bioscience for Paramedics units with the introduction of guided-inquiry learning, as well as other active learning strategies, and assesses their impact on student performance. Results indicate that active learning used within a classroom and in the large lecture theater setting improved students’ grades with positive student perception of their learning experience. [ABSTRACT FROM AUTHOR]

Evidence shows that factors contributing to success in physiology education for allied health students at universities include not only their high school achievement and background but also factors such as confidence with their teachers and quality of their learning experience, justifying intensive and continued survey of students' perceptions of their learning experience. Here we report data covering a 3-yr period in a physiology subject that has been redesigned for blended and online presentation. Consistent with previous reports, we show that when we undertook a blended mode of delivery, students demonstrated better grades than traditional modes of teaching; however the absence of didactic teaching in this subject resulted in lower grades overall. Students have very strong positive attitudes to weekly quizzes (80% positive approval) but report ambivalent attitudes to online self-directed learning (61% negative perception), even though they had 2-h weekly facilitated workshops. Overwhelmingly, students who undertook the subject in a selfdirected online learning mode requested more face-to-face-teaching (70% of comments). From these data, we suggest that there is a quantifiable benefit to didactic teaching in the blended teaching mode that is not reproduced in online self-directed learning, even when face-to-face guided inquiry-based learning is embedded in the subject. [ABSTRACT FROM AUTHOR]

The study of human bioscience is viewed as a crucial curriculum in allied health. Nevertheless, bioscience (and particularly physiology) is notoriously difficult for undergraduates, particularly academically disadvantaged students. So endemic are the high failure rates (particularly in nursing) that it has come to be known as "the human bioscience problem." In the present report, we describe the outcomes for individual success in studying first-year human physiology in a subject that emphasises team-based active learning as the major pedagogy for mastering subject learning outcomes. Structural equation modeling was used to develop a model of the impact team learning had on individual performance. Modeling was consistent with the idea that students with similar academic abilities (as determined by tertiary entrance rank) were advantaged (scored higher on individual assessment items) by working in strong teams (teams that scored higher in team-based assessments). Analysis of covariance revealed that students who studied the subject with active learning as the major mode of learning activities outperformed students who studied the subject using the traditional didactic teaching format (lectures and tutorials, P = 0.000). After adjustment for tertiary entrance rank (via analysis of covariance) on two individual tests (the final exam and a late-semester in-class test), individual student grades improved by 8% (95% confidence interval: 6-10%) and 12% (95% confidence interval: 10-14%) when students engaged in team-based active learning. These data quantitatively support the notion that weaker students working in strong teams can overcome their educational disadvantages. [ABSTRACT FROM AUTHOR]

A reduction of heat loss to the environment through increased cutaneous vasoconstrictor (CVC) sympathetic outflow contributes to elevated body temperature during fever. We determined the role of neurons in the dorsomedial hypothalamus (DMH) in increases in CVC sympathetic tone evoked by PGE2 into the preoptic area (POA) in chloralose/urethane-anesthetized rats. The frequency of axonal action potentials of CVC sympathetic ganglion cells recorded from the surface of the tail artery was increased by 1.8 Hz following nanoinjections of bicuculline (50 pmol) into the DMH. PGE2 nanoinjection into the POA elicited a similar excitation of tail CVC neurons (+2.1 Hz). Subsequent to PGE2 into the POA, muscimol (400 pmol/side) into the DMH did not alter the activity of tail CVC neurons. Inhibition of neurons in the rostral raphé pallidus (rRPa) eliminated the spontaneous discharge of tail CVC neurons but only reduced the PGE2-evoked activity. Residual activity was abolished by subsequent muscimol into the rostral ventrolateral medulla. Transections through the neuraxis caudal to the POA increased the activity of tail CVC neurons, which were sustained through transections caudal to DMH. We conclude that while activation of neurons in the DMH is sufficient to activate tail CVC neurons, it is not necessary for their PGE2-evoked activity. These results support a CVC component of increased core temperature elicited by PGE2 in POA that arises from relief of a tonic inhibition from neurons in POA of CVC sympathetic premotor neurons in rRPa and is dependent on the excitation of CVC premotor neurons from a site caudal to DMH. [ABSTRACT FROM AUTHOR]

Background: Cannabinoids, the active components of marijuana, stimulate appetite, and cannabinoid receptor-1 (CB1-R) antagonists suppress appetite and promote weight loss. Little is known about how CB1-R antagonists affect the central neurocircuitry, specifically the melanocortin system that regulates energy balance. Methodology/Principal Findings: Here, we show that peripherally administered CB1-R antagonist (AM251) or agonist equally suppressed or stimulated feeding respectively in Ay , which lack a functional melanocortin system, and wildtype mice, demonstrating that cannabinoid effects on feeding do not require melanocortin circuitry. CB1-R antagonist or agonist administered into the ventral tegmental area (VTA) equally suppressed or stimulated feeding respectively, in both genotypes. In addition, peripheral and central cannabinoid administration similarly induced c-Fos activation in brain sites suggesting mediation via motivational dopaminergic circuitry. Amperometry-detected increases in evoked dopamine (DA) release by the CB1-R antagonist in nucleus accumbens slices indicates that AM251 modulates DA release from VTA terminals. Conclusions/Significance: Our results demonstrate that the effects of cannabinoids on energy balance are independent of hypothalamic melanocortin circuitry and is primarily driven by the reward system. [ABSTRACT FROM AUTHOR]

Abstract: Central inhibitory pathways play a significant role in determining the level of sympathetic outflow to the cold defense efferents in mammals. We tested the hypothesis that neurons in the rostral ventromedial periaqueductal gray (rvmPAG) are a source of inhibitory regulation of the sympathetic nerve activity (SNA) to brown adipose tissue (BAT). In urethane/chloralose-anesthetized, paralyzed, artificially ventilated rats, microinjection of PGE2 (200 pmol in 70 nl) into the medial preoptic area (POA) or microinjection of the GABAA antagonists, bicuculline or SR95531 (60 pmol in 60 nl), into the dorsomedial hypothalamic area (DMH) increased BAT SNA by +853 ± 176 and +898 ± 249% of control, respectively. These evoked increases in BAT SNA were reversed by microinjection of bicuculline (60 pmol in 60 nl) into the rvmPAG at the level of the posterior commissure. Microinjection of muscimol (160 pmol in 80 nl) into the rvmPAG increased BAT SNA by an amount (+191 ± 92% of control) that was significantly (P < 0.05) smaller than the peak increase observed after bicuculline microinjection into the rostral raphe pallidus (+1340 ± 547% of control), but not different from that observed after transaction of the midbrain posterior to the rvmPAG (+423 ± 123% of control). We conclude that the rvmPAG contains neurons that exert an inhibitory influence on the sympathetic outflow to BAT. These BAT sympathoinhibitory neurons are, themselves, under a tonic GABAergic inhibition. Blockade of this tonic inhibition reveals an inhibitory influence of rvmPAG neurons that is capable of reversing BAT SNA activations from POA or from DMH. Augmenting the tonic inhibition of rvmPAG neurons elicits a modest increase in BAT SNA. Neurons in rvmPAG provide some, but not all, of the tonic inhibition regulating the discharge of BAT sympathetic premotor neurons in RPa and ultimately the level of thermogenesis in BAT. [Copyright &y& Elsevier]

In mammals, brown adipose tissue (BAT) is activated rapidly in response to cold in order to maintain body temperature. Although BAT has been studied greatly in small animals, it is difficult to measure the activity of BAT in humans. Therefore, little is known about the heat-generating capacity and physiological significance of BAT in humans, including the degree to which components of the diet can activate BAT. This is due to the limitations in the currently most used method to assess the activation of BAT-radiolabeled glucose (fluorodeoxyglucose or 18 FDG) measured by positron emission tomography-computerized tomography (PET-CT). This method is usually performed in fasted subjects, as feeding induces glucose uptake by the muscles, which can mask the glucose uptake into the BAT. This paper describes a detailed protocol for quantifying total-body human energy expenditure and substrate utilization from BAT thermogenesis by combining indirect calorimetry, infrared thermography, and blood glucose monitoring in carbohydrate-loaded adult males. To characterize the physiological significance of BAT, measures of the impact of BAT activity on human health are critical. We demonstrate a protocol to achieve this by combining carbohydrate loading and indirect calorimetry with measurements of supraclavicular changes in temperature. This novel approach will help to understand the physiology and pharmacology of BAT thermogenesis in humans.