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[O.sub.2] chemoreceptors elicit cardiorespiratory reflexes in all vertebrates, but consensus on [O.sub.2]-sensing signal transduction mechanism(s) is lacking. We recently proposed that hydrogen sulfide ([H.sub.2]S) metabolism is involved in [O.sub.2] sensing in vascular smooth muscle. Here, we examined the possibility that [H.sub.2]S is an [O.sub.2] sensor in trout chemoreceptors where the first pair of gills is a primary site of aquatic [O.sub.2] sensing and the homolog of the mammalian carotid body. Intrabuccal injection of [H.sub.2]S in unanesthetized trout produced a dose-dependent bradycardia and increased ventilatory frequency and amplitude similar to the hypoxic response. Removal of the first, but not second, pair of gills significantly inhibited [H.sub.2]S-mediated bradycardia, consistent with the loss of aquatic chemoreceptors, mRNA for [H.sub.2]S-synthesizing enzymes, cystathionine [beta]-synthase and cystathionine [gamma]-lyase, was present in branchial tissue. Homogenized gills produced [H.sub.2]S enzymatically, and [H.sub.2]S production was inhibited by [O.sub.2], whereas mitochondrial [H.sub.2]S consumption was [O.sub.2] dependent. Ambient hypoxia did not affect plasma [H.sub.2]S in unanesthetized trout, but produced a [Po.sub.2]-dependent increase in a sulfide moiety suggestive of increased [H.sub.2]S production. In isolated zebrafish neuroepithelial cells, the putative chemoreceptive cells of fish, both hypoxia and [H.sub.2]S, produced a similar ~10-mV depolarization. These studies are consistent with [H.sub.2]S involvement in [O.sub.2] sensing/signal transduction pathway(s) in chemoreceptive cells, as previously demonstrated in vascular smooth muscle. This novel mechanism, whereby [H.sub.2]S concentration ([[H.sub.2]S]) is governed by the balance between constitutive production and oxidation, tightly couples tissue [[H.sub.2]S] to [Po.sub.2] and may provide an exquisitely sensitive, yet simple, [O.sub.2] sensor in a variety of tissues. hydrogen sulfide concentration

Hydrogen sulfide ([H.sub.2]S) is rapidly emerging as a biologically significant signaling molecule. Studies published before 2000 report low or undetectable [H.sub.2]S (usually as total sulfide) levels in blood or plasma, whereas recent work has reported sulfide concentrations between 10 and 300 [micro]M, suggesting it acts as a circulating signal. In the first series of experiments, we used a recently developed polarographic sensor to measure the baseline level of endogenous [H.sub.2]S gas and turnover of exogenous [H.sub.2]S gas in real time in blood from numerous animals, including lamprey, trout, mouse, rat, pig, and cow. We found that, contrary to recent reports, [H.sub.2]S gas was essentially undetectable (< 100 nM total sulfide) in all animals. Furthermore, exogenous sulfide was rapidly removed from blood, plasma, or 5% bovine serum albumin in vitro and from intact trout in vivo. To determine if blood [H.sub.2]S could transiently increase, we measured oxygen-dependent [H.sub.2]S production by trout hearts in vitro and in vivo. [H.sub.2]S has been shown to mediate ischemic preconditioning (IPC) in mammals. [PC is present in trout and, unlike mammals, the trout myocardium obtains its oxygen from relatively hypoxic systemic venous blood. In vitro, myocardial [H.sub.2]S production was inversely related to P[O.sub.2], whereas we failed to detect [H.sub.2]S in ventral aortic blood from either normoxic or hypoxic fish in vivo. These results provide an autocrine or paracrine mechanism for myocardial coupling of hypoxia to [H.sub.2]S in [PC, i.e., oxygen sensing, but they fail to provide any evidence that [H.sub.2]S signaling is mediated by the circulation. gasotransmitter; hydrogen sulfide metabolism; vascular signaling

Trout are of interest in defining the relationship between fluid and salt balance on cardiovascular function because they thrive in freshwater (FW; volume loading, salt depleting), saltwater (SW; volume depleting, salt loading), and FW while fed a high-salt diet (FW-HS; volume and salt loading). The effects of chronic (>2 wk) adaptation to these three protocols on blood volume ([sup.51]Cr red cell space), extracellular fluid volume ([sup.99m]Tc-diethylene triaminepenta-acetic acid space), arterial (dorsal aortic; PDA) and venous (ductus Cuvier; [P.sub.ven) blood pressure, mean circulatory filling pressure (zero-flow [P.sub.ven]), and vascular capacitance were examined in the present study on unanesthetized rainbow trout. Blood volume, extracellular fluid volume, [P.sub.DA], [P.sub.ven], and mean circulatory filling pressure progressively increased in the order SW < FW < FW-HS. Vascular capacitance in SW fish appeared to be continuous with the capacitance curve of FW fish and reflect a passive volume-dependent unloading of the venous system of FW fish. Vascular capacitance curves for FW-HS fish were displaced upward and parallel to those of FW fish, indicative of an active increase in unstressed blood volume without any change in vascular compliance. These studies are the first in any vertebrate to measure the relationship between fluid compartments and cardiovascular function during independent manipulation of volume and salt balance, and they show that volume, but not salt, balance is the primary determinant of blood pressure in trout. They also present a new paradigm with which to investigate the relative contributions of water and salt balance in cardiovascular homeostasis. fish; unstressed blood volume; mean circulatory filling pressure; osmoregulation; ionoregulation

Experiments were conducted on rainbow trout to determine the impact of dietary salt on arterial blood pressure. After 4-6 wk, fish fed a salt-enriched diet exhibited a 37% elevation of dorsal aortic pressure (from 23.8 [+ or -]1.2 to 32.6 [+ or -] 1.4 mmHg) and an 18% increase in ventral aortic pressure (from 33.0 [+ or -] 1.5 to 38.9 [+ or -] 1.3 mmHg). The hypertension presumably reflected the increase in cardiac output (from 31.0 [+ or -] 0.8 to 36.4 [+ or -] 2.2 ml.[min.sup.-1]. [kg.sup.-1]) because systemic and branchial resistances were statistically unaltered by salt feeding. The chronic hypertension was associated with a decrease in the pressor responses of the systemic vasculature to catecholamines and hypercapnia in the salt-fed fish. The reduction in [alpha]-adrenergic responsiveness of the systemic vasculature is consistent with desensitization or loss of functional [alpha]-adrenoceptors ([alpha]-ARs). In support of this idea, the salt-fed fish exhibited significantly decreased levels of [[alpha].sub.1D]-AR mRNA in the dorsal aorta and the afferent (ABA) and efferent branchial arteries (EBA). In contrast, however, the results obtained from norepinephrine doseresponse curves for EBA and ABA vascular rings in vitro did not provide evidence for loss of function of branchial artery [[alpha].sub.1]-ARs in the salt-fed fish. Indeed, the [EC.sub.50] for the EBA norepinephrine doseresponse curve was significantly reduced (from 3.75 x [10.sup.-7] to 2.12 x [10.sup.-7] M) in the salt-fed fish, indicating an increase in the binding affinity of the [[alpha].sub.1]-ARs. norepinephrine; epinephrine; blood pressure; systemic resistance; salt feeding; hypercapnia; efferent branchial artery; afferent branchial artery

Hydrogen sulfide ([H.sub.2]S) is a recently identified endogenous vasodilator in mammals. In steelhead/ rainbow trout (Oncorhynchus mykiss, Osteichthyes), [H.sub.2]S produces both dose-dependent dilation and a unique dose-dependent constriction. In this study, we examined [H.sub.2]S vasoactivity in all vertebrate classes to determine whether [H.sub.2]S is universally vasoactive and to identify phylogenetic and/or environmental trends. [H.sub.2]S was generated from NaHS and examined in unstimulated and precontracted systemic and, when applicable, pulmonary arteries (PA) from Pacific hagfish (Eptatretus stouti, Agnatha), sea lamprey (Petromyzon marinus, Agnatha), sandbar shark (Carcharhinus milberti, Chondrichthyes), marine toad (Bufo marinus, Amphibia), American alligator (Alligator mississippiensis, Reptilia), Pekin duck (Anas platyrhynchos domesticus, Ayes), and white rat (Rattus rattas, Mammalia). In otherwise unstimulated vessels, NaHS produced 1) a dose-dependent relaxation in Pacific hagfish dorsal aorta; 2) a dose-dependent contraction in sea lamprey dorsal aorta, marine toad aorta, alligator aorta and PA, duck aorta, and rat thoracic aorta; 3) a threshold relaxation in shark ventral aorta, dorsal aorta, and afferent branchial artery and 4) a multiphasic contraction-relaxation-contraction in the marine toad PA, duck PA, and rat PA. Precontraction of these vessels with another agonist did not affect the general pattern of NaHS vasoactivity with the exception of the rat aorta, where relaxation was now dominant. These results show that [H.sub.2]S is a phylogenetically ancient and versatile vasoregulatory molecule that appears to have been opportunistically engaged to suit both organspecific and species-specific homeostatic requirements. cardiovascular; fish; amphibian; reptile: bird; mammal: evolution

Relations were examined between configurations of Big Five Traits (Extraversion, Agreeableness, Conscientiousness, Neuroticism, Openness to Experience) and 16 fundamental motives (Social Contact, Curiosity, Honor, Power, Order, Idealism, Independence, Status, Vengeance, Romance, Family, Activity, Saving, Acceptance, Eating, Tranquility) in 138 university students (93 women, 45 men; M age = 20.3 yr., SD = 4.5). Big Five traits were measured with the NEO-PI-R and motives were measured with the Reiss Profile of Fundamental Goals and Motivation Sensitivities. The traits were significantly related with all the motives (adjusted [R.sup.2] = .06 to .43) except Physical Activity. Four motives were related with only one trait and nine configurations of two or more traits were correlated with the remaining 11 motives. Total motive scores across all participants, an index of the strength of overall motivation, were positively correlated with Extraversion and Neuroticism and negatively with Agreeableness.

Dombkowski, Ryan A., Michael J. Russell, and Kenneth R. Olson. Hydrogen sulfide as an endogenous regulator of vascular smooth muscle tone in trout. Am J Physiol Regul Integr Comp Physiol 286: R678-R685, 2004; 10.1152/ajpregu.00419.2003.--Hydrogen sulfide ([H.sub.2]S) is an endogenous vasodilator in mammals, but its presence and function in other vertebrates is unknown. We generated [H.sub.2]S from NaHS and examined the effects on isolated efferent branchial arteries from steelhead (stEBA) or rainbow (rtEBA) trout. [H.sub.2]S concentration was measured colorimetrically (CM) and with ion-selective electrodes (ISE) in rainbow trout plasma. NaHS produced a triphasic response consisting of a relaxation (phase 1), constriction (phase 2), and relaxation (phase 3) in both unstimulated vessels and in stEBA precontracted with carbachol (Carb). Phase 1 and phase 3 in stEBA were decreased and phase 2 increased in unstimulated vessels by [[K.sup.+].sub.ATP] channel inhibition (glibenclamide), or a cocktail of inhibitors of cyclooxygenase, lipoxygenase, and cytochrome P-450 (indomethacin, esculetin, and clotrimazole). Inhibition of soluble guanylate cyclase with ODQ or NS-2028 inhibited phase 3 in stEBA, although NaHS decreased cGMP production by rtEBA. stEBA phase 2 contractions were partially inhibited by the myosin light chain kinase inhibitor, ML-9, but unaffected by L-type calcium channel inhibition (methoxyverapamil), whereas contraction in rtEBA was partially inhibited by nifedipine or removal of extracellular calcium. Phase 3 relaxations were more pronounced in stEBA precontracted with Carb and norepinephrine (NE) than those contracted by KCl or [K.sub.2]S[O.sub.4]. stEBA phase 2 and phase 3 responses were dose dependent(E[C.sub.50] = 1.1 [+ or -] 1.2 x [10.sup.-3] M and 6.7 [+ or -] 0.9 x [10.sup.-5] M, respectively; n = 7). NaHS was also vasoactive in steelhead bulbus arteriosus, celiacomesenteric arteries, and anterior cardinal veins. Rainbow trout plasma sulfide concentration was 4.0 [+ or -] 0.3 x [10.sup.-5] M, n = 4 (CM) and 3.8 [+ or -] 0.4 x [10.sup.-5] M, n = 9 (ISE); similar to phase 3 E[C.sub.50]. Because NaHS has substantial vasoactive effects at physiological plasma concentrations, we propose that its soluble derivative, [H.sub.2]S, is a tonically active endogenous vasoregulator in trout. fish; cardiovascular; guanosine 3',5'-cyclic monophosphate; vasodilator; vasoconstrictor

Measurement of venous function in vivo is inherently difficult. In this study, we used the Hilbert transform to examine the dynamic relationships between venous pressure and cardiac output (CO) in rainbow trout whose blood volume was continuously increased and decreased by ramp infusion and withdrawal (I/W). The dorsal aorta and ductus Cuvier were cannulated percutaneously and connected to pressure transducers; a flow probe was placed around the ventral aorta. Whole blood from a donor was then I/W via the dorsal aortic cannula at a rate of 10% of the estimated blood volume per minute, and the duration of I/W was varied from 40, 60, 80, 90, 120, 230, 240, 260, 300, and 340 s. Compliance [change in ([Delta]) blood vol/Avenous pressure] was 2.8 [+ or -] 0.2 ml * mm[Hg.sup.-1] * [g.sup.1] (N = 25 measurements; 6 fish with closed pericardium) and 2.8 [+ or -] 0.3 ml* mm[Hg.sup.-1] * [kg.sup.1] (N = 19 measurements, 4 fish with open pericardium). Compliance was positively correlated with the duration of I/W, indicative of cardiovascular reflex responses at longer I/W durations. In trout with closed pericardium, CO followed venous pressure oscillations with an average time lag of 4.2 [+ or -] 1.0 s (N = 9); heart rate (HR) was inversely correlated with CO. These studies show that CO is entrained by modulation of venous pressure, not by HR. Thus, although trout have a rigid pericardium, venous pressure (vis-a-tergo), not cardiac suction (vis-a-fronte), appears to be the primary determinant of CO. Estimation of venous compliance by ramp-modulation of venous pressure is faster and less traumatic than classical capacitance measurements and appears applicable to a variety of vertebrate species, as does the Hilbert transform, which permits analysis of signals with disparate frequencies. fish cardiovascular system; blood transit time; cardiovascular time series; vascular compliance; Hilbert transform

The term 'soil quality' came into vogue in the 1990's following a 1993 National Research Council Committee (NRCC) report on long-range soil and water conservation entitled 'Soil and water quality: [...]

Experiment 1 examined whether the use of the DSM-III-R decision trees increased the accuracy of DSM-III-R diagnoses. Results indicated that the use of the decision trees interacted with the level of DSM-III-R experience to affect diagnostic accuracy. The use of the decision trees resulted in a modest increase in diagnostic accuracy for participants with less DSM-III-R experience; for participants with more DSM-III-R experience, the use of the decision trees had no significant effect on diagnostic accuracy. Experiment 2 examined whether the use of the DSM-III-R decision trees increased the accuracy and confidence and decreased the time of DSM-III-R diagnosis across participants with varying levels of DSM-III-R experience. The primary analyses consisted of a 3 x 2 x 2-multivariate analysis of variance (MANOVA) to determine whether the use of the decision trees increased diagnostic accuracy and diagnostic confidence and decreased diagnostic time. Results indicated (1) the experienced participants made more accurate diagnoses than the less-experienced and no-experience participants; (2) the decision trees, combined with practice, increased class diagnostic accuracy and decreased diagnostic time; and (3) participants were more confident in their diagnosis when they used the decision trees than when they did not use the decision trees. Supplementary analyses consisted of two one-way analysis of variance (ANOVA) procedures and indicated that participants' preference for and knowledge of how to use the decision trees did not significantly affect their diagnostic accuracy.

Two protocols were used in the investigation of the sympathetic nervous system regulation of venous function in the rainbow trout. Various cardiovascular parameters were monitored in the course of the experiments which also included agonists and receptor blocking studies. Results reveal that the venous system in rainbow trout is responsive to epinephrine. It responds by mobilizing blood from unstressed to stressed compartments and by decreasing compliance.

The effects of natriuretic peptides and nitroprusside on trout venous function were examined. The trout were instrumented with pressure cannulas in the ventral aorta, dorsal aorta and ductus Cuvier while simultaneously monitoring the cardiac output during natriuretic peptide (NP) infusion. Results showed that NP decreased venous compliance, which in turn, resulted to a decrease in venous return.

The cardiac function of conscious Oncorhynchus mykiss trout was analyzed after the adminsitration of [Arg0,Trp5,Leu8]bradykinin (tBK) to determine the cardiovascular effects of the homologous BK. A triphasic pressor-depressor-pressor response was induced by tBK injections in conscious trout. The cardiovascular effects of tBK on Oncrohynchus mykiss was also mediated by several vasoactive systems that acted in multiple cardiovascular effectors.

Urotensin II is a 12-amino acid residue peptide localized in the tissues of the central nervous system in teleost fish. It shares high homology with somatostatin-14, and has been suggested to play an important role in the maintenance of cardiovascular function. Herein, it is shown that injections of a synthetic replicate the peptide causes an increase in blood pressure, heart rate, and cardiac output accompanied by bradycardia. It also caused vasoconstriction of efferent branchial arteries.

A study on tachykinins, a family of polypeptides, taken from the stomach of bowfin Amia calva shows that they have new structural features. Vascular resistance, arterial blood pressure and cardiac output are affected by these peptides. One peptide has substance P-like immunoreactivity, with amino acid sequences containing COOH-terminal. Another tachykinin has neurokinin A-like immunoreactivity with 23 amino acid residues. There is a partial structural similarity to mammalian peptides.

Angiotensin II (ANG-II) relaxation is an endothelium-dependent mechanism, which is initiated by the release of prostanoids. ANG-II relaxation is vessel-specific and in vivo. It possesses pressor activity and prevents hypotension. This relaxation is a significant feature of trout conductance and capacitance vessels.

The development of air-breathing organs in bimodally breathing fish has necessitated a degree of vascular remodelling in order to enhance gas exchange and support other homeostatic activities. Macrocirculatory changes include several plumbing schemes that allow perfusion of the gills, air-breathing organ, and systemic circulations in a variety of in-parallel and in-series arrangements. The incorporation of structural adaptations designed to minimize admixture of oxygenated and deoxygenated blood in transit through the heart as well as vascular shunts further increases the efficiency of the gas exchange process. A number of anatomical modifications in capillary architecture and endothelial cell structure are found in air-breathing fish and appear to be unique to these vertebrates. The physiological significance of the microcirculatory adaptations remains, to a large extent, speculative.

The gut of the elasmobranch fish, Scyliorhinus canicula, reveals tachykinins, scyliorhinin I and II, which are observed between the peptides and the amphibian tachykinins physalaemin and (Glu2,Pro5)kassinin. Association is also noted between mammalian tachykinins and tachykinins separated from the brains of teleost fish. Trout intestine shows substance P and neurokinin A (NKA) associated peptides which vary from mammalian peptides by three and two amino acids, respectively. They are duplicates of tachykinins in trout brain.

A single transit through the gill vasculature of an unanesthetized trout is used in the qualification of atrial natriuretic peptide (I 125-ANP) extraction from plasma. The Co-80 EDTA is measured after 1 hour of I 125-ANP along with the determination of the tissue distribution. The measurements insdicated the existence of I 125 bolus injected into the trout is depleted from th blood circulation before 2 minutes. These indicate that the gills are the one of the main places where the ANP is removed from the ciruclation.

Two studies examined individual differences in self-presentation style. In Study 1, American students provided ratings of actual self and presented self on personality traits of varying levels of social desirability. Three major groups were identified: consistents, flexible-impression managers, and rigid-impression managers. Differences in self-evaluations among these groups were found, with consistents rating themselves most favorably. In Study 2, the effect of experimental manipulation on consistency and favorability of self-ratings of subjects with different self-presentation styles were examined. Results demonstrated that individuals' behavior corresponded to their self-reported style. Differential tactics of self-presentation were also evident between individuals with different styles. These tactics involved the tendency either to attribute positive characteristics to the self or to deny negative characteristics.