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It is suggested that obestatin can stimulate the secretion of pancreatic juice in rats and this effect is abolished by vagotomy. Thus, the aim of the present study was to further elucidate the mechanism by which obestatin controls the exocrine pancreas secretion. Anesthetized male Wistar rats (200 ± 15 g body weight) were administered intravenously (iv) and intraduodenaly (id) every 30 min obestatin in boluses of 30, 100 and 300 nmol · kg-1 body weight and 15 min later pancreatic-biliary juice (PBJ) was collected to determine the PBJ volume, total protein and enzymes activity. Obestatin injections were also done following subdiaphragmatic vagotomy, capsaicin deafferentation and pharmacological blockage of the mucosal cholecystokinin 1 (CCK1) receptor with tarazepide. Dispersed acinar cells were isolated from rat pancreas by collagenase digestion, stimulated with CCK-8 (10-10 M) and incubated with obestatin (10-9-10-6 M) in vitro. It was noted that iv and id obestatin administrations did not affect the PBJ volume but increased protein and trypsin outputs regardless way of administration, and amylase and lipase outputs after id injection. Similarly to vagotomy, the capsaicin and tarazepide pre-treatments abolished the effects of obestatin. In contrast to the in vivo experiment, the treatment of dispersed pancreatic cells with the CCK-8+obestatin combination showed that obestatin decreased the CCK-8-stimulated amylase release from acinar cells in vitro, but obestatin alone did not exert effect on amylase release. So, it is thought that obestatin can stimulate the exocrine pancreas secretion via an indirect vagal mechanism, whilst its direct action on the acinar cells is also possible but with the opposite effects. [ABSTRACT FROM AUTHOR]

Background: CCK1 (cholecystokinin receptor 1) and protein lysine acetylation were associated with several cancers, respectively. However, whether they are involved in the alternation of gallbladder carcinoma is unknown. Aims: This study investigated the characteristics of CCK1 and protein lysine acetylation in GBC-SD cells and carcinoma of gallbladder. Methods: The expression and localization of CCK1 were detected by western blot analysis and indirect immunofluorescence. GBC-SD cells were treated with CCK-8 and CCK-8+CCK1 inhibitor. The protein lysine acetylation from cells, as well as tissues of gallbladder carcinoma, was examined by western blotting. Results: CCK1 receptor was expressed and localized in the GBC-SD cells. The synthetic octapeptide of CCK (CCK-8) could accelerate the lysine acetylation of a subset of proteins in dose-dependent manners in GBC-SD cells. Further investigation demonstrated that the specific inhibitor (CR1409) of CCK1 receptor could attenuate the CCK8-induced increase of protein lysine acetylation. In addition, we revealed that the rise of CCK1 receptor expression is associated with the increase of protein lysine acetylation in tissues from carcinoma of gallbladder. Conclusions: CCK might regulate protein lysine acetylation via CCK1 receptor. [ABSTRACT FROM AUTHOR]

Background: Participants with functional gut disorders develop gas retention and symptoms in response to intestinal gas loads that are well tolerated by healthy subjects. To determine the role of cholecystokinin (CCK1) receptors on gas transit and tolerance in women with functional gut disorders. Methods: In 12 healthy women, and 24 women with functional gut disorders (12 dyspepsia and 12 constipation-predominant irritable bowel syndrome) gas was infused into the jejunum at 12 mL/min for 3 h with simultaneous duodenal lipid infusion (intralipid 1 kcal/min), while measuring anal gas evacuation and abdominal symptoms on a 0-6 score scale. Triple-blind paired studies during iv infusion of dexloxiglumide (2.5 mg/kg bolus plus 5 mg/kg h continuous infusion), a selective CCK1 inhibitor, or saline (control) were performed in random order. Results: During saline infusion participants with functional gut disorders developed significantly greater gas retention and abdominal symptoms than healthy subjects (394 ± 40 mL vs 265 ± 35 mL and 2.8 ± 0.3 vs 1.9 ± 0.4 highest abdominal symptom score, respectively; P < 0.05 for both). Dexloxiglumide increased gas retention in both groups (514 ± 35 mL and 439 ± 60 mL, respectively; P = 0.033 vs saline for both); however, despite the larger retention, dexloxiglumide reduced abdominal symptoms (2.3 ± 0.2 score and 0.8 ± 0.3 score, respectively; P = 0.05 vs saline for both). Post-hoc analysis showed that, the decrease in abdominal symptoms was more pronounced in those participants with functional gut disorders with higher basal abdominal symptoms than in the rest ( P = 0.037). Conclusion: Inhibition of CCK1 receptors by dexloxiglumide increases intestinal gas retention and reduces abdominal symptoms in response to by intestinal gas loads. European Clinical Trials Database (EudraCT 2005-003338-16). [ABSTRACT FROM AUTHOR]

Information concerning the cellular localization of cholecystokinin (CCK)-1 receptors has been discrepant and remained scanty at ultrastructural levels. The present immunohistochemical study at light and electron microscopic levels revealed the distinct localization of CCK1 receptors in visceral organs. Immunohistochemistry by use of a purified antibody against mouse CCK1 receptor was applied to fixed tissue sections of the pancreas, gallbladder, stomach, and intestine of mice. A silver-intensified immunogold method revealed the subcellular localization under electron microscope. The immunoreactivity for CCK1 receptors was selectively found in the basolateral membrane of pancreatic acinar cells and gastric chief cells but was absent in pancreatic islets and gastric D cells. Another intense expression in the gut was seen in the myenteric nerve plexus of the antro-duodenal region and some populations of c-Kit-expressing pacemaker cells in the duodenal musculature. The gallbladder contained smooth muscle fibers with an intense immunoreactivity of CCK1 receptors on cell surfaces. The restricted localization of CCK1 receptors on the basolateral membrane of pancreatic acinar cells and gastric chief cells, along with their absence in the islets of Langerhans and gastric D cells, provides definitive information concerning the regulatory mechanism by circulating CCK. Especially, the subcellular localization in the acinar cells completes the investigation for the detection of circulating CCK by the basolateral membrane. [ABSTRACT FROM AUTHOR]

Abstract: Cholecystokinin (CCK) directly activates vagal afferent neurons resulting in coordinated gastrointestinal functions and satiation. In vitro, the effects of CCK on dissociated vagal afferent neurons are mediated via activation of the vanilloid family of transient receptor potential (TRPV) cation channels leading to membrane depolarization and an increase in cytosolic calcium. However, the cellular transduction pathway(s) involved in this process between CCK receptors and channel opening have not been identified. To address this question, we monitored CCK-induced cytosolic calcium responses in dissociated nodose neurons from rat in the presence or absence of reagents that interact with various intracellular signaling pathways. We found that the phospholipase C (PLC) inhibitor U-73122 significantly attenuated CCK-induced responses, whereas the inactive analog U-73433 had no effect. Responses to CCK were also cross-desensitized by a brief pretreatment with m-3M3FBS, a PLC stimulator. Together these observations strongly support the participation of PLC in the effects of CCK on vagal afferent neurons. In contrast, pharmacological antagonism of phospholipase A2, protein kinase A, and phosphatidylinositol 3-kinase revealed that they are not critical in the CCK-induced calcium response in nodose neurons. Further investigations of the cellular pathways downstream of PLC showed that neither protein kinase C (PKC) nor generation of diacylglycerol (DAG) or release of calcium from intracellular stores participates in the response to CCK. These results suggest that alteration of membrane phosphatidylinositol 4,5-bisphosphate (PIP2) content by PLC activity mediates CCK-induced calcium response and that this pathway may underlie the vagally-mediated actions of CCK to induce satiation and alter gastrointestinal functions. [Copyright &y& Elsevier]

Abstract: Cannabinoid CB1 receptor and cholecystokinin-1 (CCK1) receptors are located in peripheral nerve terminals of the gut, where they mediate satiety signals. Here we describe a detailed analysis of the interaction of both receptors in the control of feeding of food-deprived rats. Male Wistar rats were deprived for food 24h before testing. Rats were pre-treated with SR141716A (Rimonabant) or WIN 55,212-2 before CCK-8 sulphated administration and tested for food intake 60, 120 and 240min after last drug injection. In parallel, the effect of Lorglumide – a CCK1 receptor antagonist – pre-treatment was evaluated on feeding behaviour after SR141716A administration. Results show that SR141716A activates c-Fos expression in brainstem areas receiving vagal inputs. Blockade of CB1 receptors with SR141716A (1mg/kg) reduces feeding and display additive satiety induction with the CCK1 receptor agonist CCK-8 sulphated (5, 10, 25μg/kg). The effect of SR141716A is not blocked by Lorglumide (10mg/kg), indicating independent sites of action. Conversely, the administration of the CB1 agonist WIN 55,212-2 (2mg/kg) reduced satiety induced by CCK-8. In conclusion, these results report additive anorectic actions for CCK1 activation and peripheral CB1 receptor blockade providing a framework for combined therapies in the treatment of eating disorders. [Copyright &y& Elsevier]

Abstract: Cholecystokinin (CCK) activates the myenteric neurons of adult rats. The goal of this work is to determine the ontogeny of this activation by CCK-8 in the myenteric plexus of the duodenum (2cm immediately following the pyloric sphincter aborally) and compare it with that of the dorsal vagal complex (DVC) – which occurs in 1-day old pups. Despite the existence of both of the CCK receptors, CCK1 and CCK2, in 4, 14, 21 and 35 day old rats, CCK-8 (0, 5, 10, 20 and 40μg/kg, i.p.) increased Fos-like immunoreactivity (Fos-LI, a marker for neuronal activation) in the myenteric neurons of 21- and 35-day old rats but in the DVC of all age groups. As such, this belated activation of myenteric neurons by CCK-8 compared to the DVC may reflect a delayed role for these neurons in CCK-related functions. [ABSTRACT FROM AUTHOR]

Abstract: The anti-hypertensive peptide Arg-Ile-Tyr, which was isolated based on its inhibitory activity (IC50 =28μM) for angiotensin I-converting enzyme (ACE) from the subtilisin digest of rapeseed protein, exhibited vasorelaxing activity (EC50 =5.1μM) in an endothelium-dependent manner in the mesenteric artery of spontaneously hypertensive rats (SHRs). We named the peptide rapakinin. ACE inhibitors are reported to induce nitric oxide (NO)-dependent vasorelaxation by elevating the endogenous bradykinin level; however, the vasorelaxation induced by 10μM of rapakinin was blocked only insignificantly by HOE140 or N G-nitro-l-arginine methyl ester (l-NAME), antagonists of bradykinin B2 receptor and an inhibitor of NO synthase, respectively. On the other hand, the vasorelaxation induced by 10μM rapakinin was significantly blocked by indomethacin and CAY10441, a cyclooxygenase (COX) inhibitor and an antagonist of the IP receptor, respectively. The vasorelaxing activity of rapakinin was also blocked by lorglumide, an antagonist of the cholecystokinin (CCK) CCK1 receptor, although rapakinin has no affinity for the IP and CCK1 receptors. The vasorelaxation induced by 10μM iloprost, an IP receptor agonist, was also blocked by lorglumide, suggesting that CCK–CCK1 receptor system is activated downstream of the PGI2–IP receptor system. The anti-hypertensive activity of rapakinin after oral administration in SHRs was also blocked by CAY10441 and lorglumide. These results suggest that the anti-hypertensive activity of rapakinin might be mediated mainly by the PGI2–IP receptor, followed by CCK–CCK1 receptor-dependent vasorelaxation. [Copyright &y& Elsevier]

Abstract: A large body of evidence has demonstrated that one mechanism by which cholecystokinin (CCK) inhibits food intake through activation of CCK1 receptors (CCK1R) on vagal afferent neurons that innervate the gastrointestinal tract and project to the hindbrain. OLETF rats, which carry a spontaneous null mutation of the CCK1R, are hyperphagic, obese, and predisposed to type 2 diabetes. Recently, by introgressing the OLETF-derived, CCK1R-null gene onto a Fischer 344 genetic background, we have been able to generate a CCK1R-deficient, congenic rat strain, F344.Cck1r−/−, that in contrast to OLETF rats, possesses a lean and normoglycemic phenotype. In the present study, the behavioral and neurobiological phenotype of this rat strain was characterized more fully. As expected, intraperitoneal injections of CCK-8 inhibited intake of chow and Ensure Plus and induced Fos responses in the area postrema and the gelatinosus, commissural and medial subdivisions of the nucleus tractus solitarius of wild-type F344.Cck1r+/+ rats, whereas CCK-8 was without effect on food intake or Fos induction in the F344.Cck1r−/− rats. F344.Cck1r−/− and F344.Cck1r+/+ rats did not differ in body weight and showed comparable weight gain when maintained on Ensure Plus for 2 weeks. Also, no difference was found in 24-h food intake, and dark-phase meal frequency or meal size between F344.Cck1r+/+ and F344.Cck1r−/− rats. As expected, blockade of endogenous CCK action at CCK1R increased food intake and blocked the effects of peripheral CCK-8 in wild-type F344.Cck1r+/+ rats. These results confirm that in rats with a F344 background, CCK-1R mediates CCK-8-induced inhibition of food intake and Fos activation in the hindbrain and demonstrate that selective genetic ablation of CCK1R is not associated with altered meal patterns, hyperphagia, or excessive weight gain on a palatable diet. [Copyright &y& Elsevier]

Abstract: Enterostatin (APGPR), an anorectic pentapeptide derived from the amino terminus of procolipase, significantly reduced serum cholesterol levels after oral administration at a dose of 100mg/kg for 3 days in mice fed a high-cholesterol-cholic acid diet. The hypocholesterolemic effect of APGPR was inhibited by pretreatment with lorglumide, an antagonist for cholecystokinin 1 (CCK1) receptor, even though APGPR does not have any affinity for CCK1 receptors. Similarly, the hypocholesterolemic activity of VPDPR, an APGPR analogue, was blocked by lorglumide. These results suggest that the hypocholesterolemic effects of APGPR and VPDPR are mediated by a CCK1 receptor-dependent mechanism. [Copyright &y& Elsevier]

Background and Purpose: Cholecystokinin (CCK) stimulates the release of amylase and lipase from the normal pancreas. However, it is not clear to what extent this occurs in the early stages of pancreatitis induced by biliary tract obstruction in the rat and whether CCK initiates an inflammatory cascade in this condition.Experimental Approach: Selective CCK1 receptor antagonists, JNJ-17156516 ((S)-(3-[5-(3,4-dichloro-phenyl)-1-(4-methoxy-phenyl)-1H-pyrazol-3-yl]-2-m-tolyl-propionic acid) and dexloxiglumide, were used to assess the response of plasma amylase and lipase to a CCK analogue, CCK8S, in normal rats and in rats with bile duct ligation.Key Results: Both antagonists suppressed CCK8S-induced elevation of plasma amylase activity in normal rats. JNJ-17156516 was more potent than dexloxiglumide (ED(50)=8.2 vs >30 micromol kg(-1) p.o.) and produced a longer lived inhibition (6 vs 2 h). Plasma amylase and lipase activity were elevated in parallel to CCK plasma concentrations after bile duct ligation and both activities were suppressed in a dose-dependent manner by JNJ-17156516 and dexloxiglumide. JNJ-17156516 was approximately 5- to 10-fold more potent than dexloxiglumide. Infusion of CCK8S to naïve rats to achieve levels similar to those observed after bile duct ligation (20 pM) increased plasma amylase activity and activated nuclear factor-kappaB in the pancreas. These effects were prevented by pretreatment with JNJ-17156516.Conclusions and Implications: The elevation of plasma amylase and lipase activity in the early stages of obstruction-induced pancreatitis is largely driven by elevation of plasma CCK concentration and activation of CCK1 receptors. These data show that CCK is an initiating factor in acute pancreatitis in the rat. [ABSTRACT FROM AUTHOR]

Abstract: Enterostatin (APGPR) found in the gastrointestinal tract and brain is an anorectic pentapeptide. We found that APGPR inhibited morphine-induced analgesia after intracerebroventricular administration in mice at a dose of 10nmol/mouse. The anti-analgesic effect of APGPR was inhibited by pretreatment with lorglumide and LY225910, antagonists for cholecystokinin 1 (CCK1) and cholecystokinin 2 (CCK2) receptors, respectively. The anti-analgesic effect of APGPR may be mediated by CCK release, since APGPR does not have affinity for CCK receptors. [Copyright &y& Elsevier]

Abstract: We previously reported that a bioactive tripeptide Arg-Ile-Tyr (RIY), which has been isolated as an inhibitor for angiotensin I-converting enzyme from the subtilisin digest of rapeseed protein, decreased blood pressure. In this study, we also found that RIY dose-dependently decreased food intake at a dose of 150mg/kg after oral administration in fasted ddY male mice. The anorexigenic action of RIY was blocked by a cholecystokinin-1 CCK1 receptor antagonist, lorglumide. RIY also decreased the gastric emptying rate at a dose of 150mg/kg and the RIY-induced delay of gastric emptying was blocked by lorglumide. However, RIY had no affinity for CCK1 receptor. Taken together, RIY decreased food intake and gastric emptying by stimulating CCK release. [Copyright &y& Elsevier]

Abstract: We utilized a diaminobenzidine reaction enhanced with nickel to compare dorsal vagal complex (DVC) and myenteric neuronal Fos-Like immunoreactivity (Fos-LI), in response to sulfated cholecystokinin-8 (CCK-8) (5, 10, 20, 40 μg/kg), among Sprague–Dawley (SD), Standard Long–Evans (SLE), Otsuka Long-Evans Tokushima Fatty (OLETF), and Long–Evans Tokushima Otsuka (LETO) rats. All rat strains but OLETF expressed Fos-LI in response to CCK-8. In addition, SD rats expressed more Fos-LI in the area postrema and myenteric neurons than SLE and LETO rats. To investigate the basis for these differences, we utilized cuprolinic blue staining, which stains neuronal cell bodies, to quantify the number of myenteric neurons, and a reverse transcriptase chain polymerase reaction to measure the gene expression of CCK1 receptor in the gut. We found that SD rats have significantly more duodenal myenteric neurons than the other strains. In addition, this strain expressed significantly higher levels of the CCK1 gene in both the duodenum and jejunum than the other strains. In conclusion, SD rats may express more myenteric Fos-LI in response to CCK due to increased numbers of myenteric neurons or more intestinal CCK1 receptors than the other strains of rats. [Copyright &y& Elsevier]

Abstract: Intestinal infusion of nutrients, such as glucose and oleic acid, increase Fos-like immunoreactivity (Fos-LI) in both the enteric nervous system and neurons of the dorsal vagal complex (DVC) of the hindbrain. To test the hypothesis that increased Fos-LI in enteric neurons and the DVC, following intestinal nutrient infusions is mediated by cholecystokinin1 receptors (CCK1), we counted enteric and DVC neurons that expressed Fos-LI following intestinal infusion of oleate or glucose, with and without pretreatment with the CCK1 receptor antagonist, lorglumide. Both oleate and glucose infusions increased Fos-LI in the DVC. Oleate also increased Fos-LI in the myenteric and submucosal plexuses of the duodenum and the jejunum, but not the ileum, while glucose only increased Fos-LI in the submucosal plexus of the ileum. The CCK1 receptor antagonist, lorglumide, abolished Fos-LI in the DVC following infusions of either oleate or glucose. In addition, lorglumide attenuated oleate-induced Fos-LI in the myenteric and submucosal plexuses of the duodenum and jejunum. However, lorglumide failed to attenuate glucose-induced Fos-LI in the submucosal plexus of the ileum. These data confirm previous reports indicating that CCK1 receptors mediate increased DVC Fos-LI following intestinal infusion of oleate or glucose. CCK1 receptors also contribute to increased Fos-LI in enteric neurons following intestinal oleate infusion. However, failure of lorglumide to attenuate the increase of Fos-LI in the ileal submucosal plexus following intestinal glucose suggests that some intestinal nutrients trigger Fos-LI induction via CCK1 receptor-independent pathways. [Copyright &y& Elsevier]

Abstract: To examine the role of cholecystokinin1 receptor (CCK1) in the activation of brainstem and myenteric neurons by CCK, we compared the ability of exogenous CCK-8 to induce Fos-like immunoreactivity (Fos-LI) in these neurons in Otsuka Long–Evans Tokushima Fatty (OLETF) rats, lacking CCK1 receptors, and Long–Evans Tokushima Otsuka (LETO) controls. Five groups (n =4rats per group) of OLETF rats, and five LETO control groups, were injected intraperitoneally (IP) with 5, 10, 20, and 40μg/kg CCK-8 or saline. Forty-micrometer brainstem sections containing the area postrema, nucleus of the solitary tract, and the dorsal motor nucleus of the vagus, and myenteric neurons of the duodenum, jejunum, and ileum underwent a diaminobenzidine reaction enhanced with nickel to reveal Fos-LI. CCK-8 did not increase Fos-LI in any of the tested neurons in the OLETF rats. CCK-8 increased Fos-LI in the brainstem of the LETO rats in a dose dependent manner. In the LETO rats only 40μg/kg CCK-8 increased Fos-LI in the myenteric plexus of the jejunum. This study demonstrates that CCK-8 activates the brainstem and myenteric neurons through the CCK1 receptor. [Copyright &y& Elsevier]

Cholecystokinin (CCK) produces contractions of gallbladder and colon in a number of different species. Although the effects of CCK on the human gallbladder are relatively well documented, the CCK receptors in the human colon have not been clearly characterised. Therefore, in this study, the CCK receptors in the human gallbladder and colon were compared using pharmacological techniques. Contraction of specimens of the human tissue was measured using in vitro organ bath bioassay. The effect of selective concentrations of CCK1 and CCK2 receptor antagonists (L-364,718 and JB93182, respectively) was determined on agonist concentration–effect (E/[A]) curves obtained by cumulative dosing with sulphated CCK. The CCK1 antagonist L-364,718 produced a rightward shift of the CCK-8S [E/[A] curve in the human gallbladder (pA2=9.15±0.26) and ascending colon (pA2=9.20±0.33). In both tissues, the CCK2 receptor antagonist, JB93182, had no effect on the CCK E/[A] curves. In addition, in the colon, pentagastrin responses were inhibited by L-364,718 but unaffected by JB93182. These data indicate that the CCK-induced contraction of the human colon and gallbladder smooth muscle is mediated solely through the CCK1 receptor subtype, and the antagonist affinity estimates are consistent with those previously obtained in experiments on animal tissue. [Copyright &y& Elsevier]

Abstract Background Cholecystokinin octapeptide (CCK-8), the most potent endogenous anti-opioid peptide, has been shown to regulate the processes of morphine dependence. In our previous study, we found that exogenous CCK-8 attenuated naloxone induced withdrawal symptoms. To investigate the precise effect of exogenous CCK-8 and the role of cholecystokinin (CCK) 1 and/or 2 receptors in morphine dependence, a SH-SY5Y cell model was employed, in which the μ-opioid receptor, CCK1/2 receptors, and endogenous CCK are co-expressed. Results Forty-eight hours after treating SH-SY5Y cells with morphine (10 μM), naloxone (10 μM) induced a cAMP overshoot, indicating that cellular morphine dependence had been induced. The CCK receptor and endogenous CCK were up-regulated after chronic morphine exposure. The CCK2 receptor antagonist (LY-288,513) at 1–10 μM inhibited the naloxone-precipitated cAMP overshoot, but the CCK1 receptor antagonist (L-364,718) did not. Interestingly, CCK-8 (0.1-1 μM), a strong CCK receptor agonist, dose-dependently inhibited the naloxone-precipitated cAMP overshoot in SH-SY5Y cells when co-pretreated with morphine. The L-364,718 significantly blocked the inhibitory effect of exogenous CCK-8 on the cAMP overshoot at 1–10 μM, while the LY-288,513 did not. Therefore, the CCK2 receptor appears to be necessary for low concentrations of endogenous CCK to potentiate morphine dependence in SH-SY5Y cells. An additional inhibitory effect of CCK-8 at higher concentrations appears to involve the CCK1 receptor. Conclusions This study reveals the difference between exogenous CCK-8 and endogenous CCK effects on the development of morphine dependence, and provides the first evidence for the participation of the CCK1 receptor in the inhibitory effects of exogenous CCK-8 on morphine dependence.

In contrast to reversible activation by agonist, cholecystokinin 1 receptor (CCK1R) is permanently activated by singlet oxygen generated in photodynamic action, with sulphonated aluminium phthalocyanine or genetically encoded mini singlet oxygen generator (miniSOG) as photosensitizer. In these works, a halogen light source was used to power photodynamic action. For possible in vivo application of photodynamic CCK1R physiology, bearing a cumbersome light-delivery device connected to an external light source by experimental animals might interfere with their behavior. Therefore, in the present work, the possibility of bioluminescence-driven miniSOG photodynamic CCK1R activation was examined, as monitored by Fura-2 calcium imaging. In parallel experiments, it was found that, after plasma membrane (PM)-localized expression of miniSOGPM in AR4-2J cells, light irradiation with blue light-emitting diode (LED) (450 nm, 85 mW·cm−2, 1.5 min) induced persistent calcium oscillations that were blocked by CCK1R antagonist devazepide 2 nM. NanoLuc was expressed bicistronically with miniSOGPM via an internal ribosome entry site (IRES) sequence (pminiSOGPM-IRES-NanoLuc). The resultant miniSOGPM-IRES-NanoLuc-AR4-2J cells were found to generate strong bioluminescence upon addition of NanoLuc substrate coelenterazine. Strikingly, coelenterazine 5 microM was found to trigger long-lasting calcium oscillations (a hallmark for permanent CCK1R activation) in perifused miniSOGPM-IRES-NanoLuc-AR4-2J cells. These data indicate that NanoLuc bioluminescence can drive miniSOGPM photodynamic CCK1R activation, laying the foundation for its future in vivo applications. [ABSTRACT FROM AUTHOR]