Biochemical reactions involved in pancreatic enzyme secretion. 2. Inhibitory effects of tetracaine and atropine

1977 ◽  
Vol 55 (3) ◽  
pp. 639-643 ◽  
Author(s):  
J. Morisset ◽  
A. R. Beaudoin
Keyword(s):  
Inhibitory Action ◽  
Pancreatic Enzyme ◽  
Pancreatic Tissue ◽  
Enzyme Secretion ◽  
Inhibitory Effects ◽  
Calcium Efflux ◽  
Inhibitory Potency ◽  
Subsequent Response ◽  
Pancreatic Enzyme Secretion

Pancreatic enzyme secretion induced by urecholine or cholecystokinin–pancreozymin (CCK–PZ) is inhibited by tetracaine. If the pancreatic tissue is preincubated with tetracaine then washed out, the subsequent response to CCK–PZ is not affected while that to urecholine is impaired. In contrast with atropine, tetracaine loses its inhibitory potency once secretion has been initiated by urecholine before the addition of the local anaesthetic. Calcium efflux studies have shown that addition of tetracaine in vitro is associated with release of calcium in the incubation medium. This effect on calcium efflux might explain partly the inhibitory action of the drug.

Biochemical Reactions Involved in Pancreatic Enzyme Secretion. I. Activation of the Adenylate Cyclase Complex

1974 ◽  
Vol 52 (2) ◽  
pp. 174-182 ◽  
Author(s):  
A. R. Beaudoin ◽  
C. Marois ◽  
J. Dunnigan ◽  
J. Morisset
Keyword(s):  
Adenylate Cyclase ◽  
Pancreatic Enzyme ◽  
Pancreatic Tissue ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Enzyme Secretion ◽  
Amylase Secretion ◽  
Biochemical Reactions ◽  
Pancreatic Enzyme Secretion

Pancreatic amylase secretion was studied using an in vitro system. Secretion was increased by urecholine and cholecystokinin–pancreozymin (CCK–PZ). Addition of tetracaine and dibucaine to the medium abolished secretion stimulated by urecholine and decreased by 75% that stimulated by CCK–PZ. In contrast, an increase in enzyme secretion was observed after dibutyryl cyclic AMP; this was potentiated by tetracaine added to the medium. Oxygen uptake by pieces of pancreatic tissue was not affected by tetracaine. Adenylate cyclase activity, increased in vitro when CCK–PZ was added to a pancreas homogenate, was inhibited by 15% by tetracaine at 2 mM and by 67.5% at the 10 mM concentration.From data known on biochemical reactions associated with the process of secretion and the results described in the present paper, we propose a model for the activation of the pancreatic adenylate cyclase complex. Associated to the depolarization of the acinar cell plasma membrane by urecholine and CCK–PZ and an inward movement of sodium and calcium, there is an immediate rise in adenylate cyclase activity within 10 s which is timed with the initiation of amylase secretion.

Somatostatin inhibits pancreatic enzyme secretion at a central vagal site

1993 ◽  
Vol 265 (2) ◽  
pp. G251-G257 ◽  
Author(s):  
Y. Li ◽  
C. Owyang
Keyword(s):  
Effective Dose ◽  
Protein Secretion ◽  
Pancreatic Secretion ◽  
Inhibitory Action ◽  
Pancreatic Enzyme ◽  
Enzyme Secretion ◽  
Afferent Pathway ◽  
Pancreatic Enzyme Secretion ◽  
Vagal Afferent ◽  
Somatostatin 14

The mechanisms and site of action of somatostatin-induced inhibition of pancreatic enzyme secretion were investigated using different stimulants of pancreatic secretion acting on different sites in anesthetized rats. Administration of graded doses of somatostatin-14 resulted in a dose-related inhibition of pancreatic protein secretion evoked by 2-deoxy-D-glucose, a central vagal stimulant that acts by stimulating the dorsal vagal nuclei. The lowest effective dose of somatostatin-14 was 1.0 microgram.kg-1 x h-1; maximal effective dose was 25 micrograms.kg-1 x h-1, which resulted in complete inhibition of protein output. Similarly, somatostatin-14 at a dose of 25 micrograms.kg-1 x h-1 also completely inhibited pancreatic protein secretion in response to a physiological concentration of cholecystokinin octapeptide (CCK-8), which acts via a vagal afferent pathway. In contrast, pancreatic protein outputs evoked by bethanechol, which directly stimulates pancreatic muscarinic receptors, or electrical stimulation of the vagal trunk, which activates the vagal efferent pathway, were unaffected by somatostatin-14. In separate studies, we demonstrated that perivagal treatment with the sensory neurotoxin capsaicin impaired pancreatic responses to CCK-8 but had no effect on the inhibitory action of somatostatin-14 on pancreatic secretion evoked by 2-deoxy-D-glucose, ruling out an effect of somatostatin on the vagal afferent pathway. Similarly we also demonstrated that perineural capsaicin treatment of the celiac-superior mesenteric ganglia did not affect the inhibitory action of somatostatin. These findings indicate that somatostatin inhibits 2-deoxy-D-glucose- and CCK-8-evoked pancreatic enzyme secretion via a vagal pathway.(ABSTRACT TRUNCATED AT 250 WORDS)

Cholecystokinin at physiological levels evokes pancreatic enzyme secretion via a cholinergic pathway

1992 ◽  
Vol 263 (1) ◽  
pp. G102-G107 ◽  
Author(s):  
H. C. Soudah ◽  
Y. Lu ◽  
W. L. Hasler ◽  
C. Owyang
Keyword(s):  
Acetylcholine Release ◽  
Pancreatic Enzyme ◽  
Exocrine Secretion ◽  
Cholinergic Innervation ◽  
Enzyme Secretion ◽  
Healthy Humans ◽  
Cholinergic Pathway ◽  
Pancreatic Enzyme Secretion ◽  
Stimulation Of

The mechanism by which physiological concentrations of cholecystokinin (CCK) evoke pancreatic exocrine secretion in humans was investigated. CCK octapeptide (CCK-8) dose dependently increased trypsin and lipase output in healthy humans. Atropine inhibited CCK-8 (10 ng.kg-1.h-1)-stimulated trypsin output by 84.0 +/- 7.7% and lipase output by 78.6 +/- 9.2%. The inhibition with atropine was much less with a CCK-8 dose of 40 ng.kg-1.h-1 (41.8 +/- 6.6% for trypsin and 46.3 +/- 7.3% for lipase). CCK-8 at 10 ng.kg-1.h-1 produced plasma CCK levels similar to postprandial levels (6.0 +/- 1.3 vs. 6.9 +/- 0.8 pM), whereas the 40-ng.kg-1.h-1 dose produced supraphysiological levels (18.4 +/- 3.1 pM). To evaluate if CCK might act via stimulation of cholinergic nerves, in vitro studies were performed using rat pancreas. CCK-8 (10 nM-10 microM) stimulated [3H]acetylcholine release from pancreatic lobules that was blocked by tetrodotoxin, a calcium-free medium, and the CCK antagonist L364,718. In conclusion, CCK-stimulated pancreatic enzyme secretion is dependent on cholinergic neural and noncholinergic pathways. In humans, CCK infusions, which produce plasma CCK levels similar to those seen postprandially, stimulate the pancreas predominantly via a pathway dependent on cholinergic innervation. Correlative in vitro experiments suggest that CCK may act by stimulation of neural acetylcholine release. In contrast, supraphysiological CCK infusions act in part via noncholinergic pathways.

Biochemical reactions involved in pancreatic enzyme secretion. 4. Effects of cytochalasin B on functions of the exocrine pancreas

1977 ◽  
Vol 55 (3) ◽  
pp. 644-651 ◽  
Author(s):  
J. Morisset ◽  
A. R. Beaudoin
Keyword(s):  
Cytochalasin B ◽  
Pancreatic Enzyme ◽  
Inhibitory Effect ◽  
Enzyme Secretion ◽  
Amylase Secretion ◽  
Calcium Efflux ◽  
Acid Accumulation ◽  
Pancreatic Enzyme Secretion ◽  
Microfilament System ◽  
Amino Acid Accumulation

These experiments were performed to evaluate the effects of cytochalasin B on pancreatic enzyme secretion and thus perhaps establish a role for microfilaments in the exocytosis process. The alkaloid at a concentration of 1 μg/ml (2 μM) inhibits amylase secretion induced by urecholine or cholecystokinin-pancreozymin (CCK-PZ) but does not modify that induced by dibutyryl cyclic AMP. The inhibitory effect of the drug is reversible after a 30-min washing out period. It does not affect O2 consumption, basal calcium efflux, or efflux caused by CCK-PZ. Amino acid accumulation in the tissue and their incorporation into proteins are not modified. It is suggested that cytochalasin B inhibits pancreatic enzyme secretion, probably through an effect on the microfilament system.

Pancreatic enzyme secretion: nonspecific stimulation by duodenal mucosal extracts

1981 ◽  
Vol 240 (2) ◽  
pp. G109-G113
Author(s):  
A. La Bella ◽  
R. G. Lahaie ◽  
H. Sarles ◽  
J. C. Dagorn
Keyword(s):  
Pancreatic Enzyme ◽  
Extraction Procedure ◽  
Pancreatic Enzymes ◽  
Enzyme Secretion ◽  
Specific Enzyme ◽  
Pancreatic Enzyme Secretion ◽  
Related Enzyme

Felber et al. (Lancet 2: 185-188, 1974) reported that duodenal extracts obtained from rats fed a given meal induced the specific secretion of related pancreatic enzymes. Such an observation challenges the generally accepted theory of parallel secretion of pancreatic enzymes. Although these experiments were faithfully reproduced, no induction of specific enzyme secretion could be obtained. Moreover, comparison of the secretagogue potency of different preparations of duodenal extract, both in vivo (anesthetized rat) and in vitro (pancreatic lobules), demonstrated that in the original extraction procedure most of the secretagogue activity was lost. Finally, even the fully active extract failed to induce specific enzyme secretion. It is therefore unlikely that duodenal extracts from rats fed a specific meal can induce selective secretion of the related enzyme.

Central CGRP inhibits pancreatic enzyme secretion by modulation of vagal parasympathetic outflow

1998 ◽  
Vol 275 (5) ◽  
pp. G957-G963 ◽  
Author(s):  
Ying Li ◽  
Yi Cheng Jiang ◽  
Chung Owyang
Keyword(s):  
Nervous System ◽  
Protein Secretion ◽  
Pancreatic Secretion ◽  
Inhibitory Action ◽  
Pancreatic Enzyme ◽  
Enzyme Secretion ◽  
Intravenous Route ◽  
Neural Pathways ◽  
Vagus Nerves ◽  
Pancreatic Enzyme Secretion

Calcitonin gene-related peptide (CGRP) is a potent inhibitor of pancreatic enzyme secretion in vivo. Recent studies have shown that CGRP exerts its inhibitory action at a central vagal site. The present study investigates the mechanism responsible for the central action of CGRP. Rats were fitted with lateral cerebroventricular cannulas, using stereotaxic instruments, 4 days before pancreatic secretion studies. In anesthetized rats, administration of 2-deoxy-d-glucose (2-DG) (75 mg/kg iv) or CCK-8 (40 pmol ⋅ kg−1 ⋅ h−1) produced a 100 and 75% increase in protein secretion, respectively, which was completely blocked by atropine. Intracerebroventricular (ICV) administration of CGRP (0.03–0.6 nmol/h) resulted in a dose-related inhibition of pancreatic protein secretion evoked by 2-DG or CCK-8. CGRP administered by the ICV route was 10–40 times more potent than CGRP given by the intravenous route. In contrast, ICV administration of CGRP had no significant effect on pancreatic protein secretion evoked by electrical vagal stimulation or bethanechol, which directly activates the pancreatic muscarinic receptor. Chemical sympathectomy induced by pretreatment with guanethedine (20 mg/kg ip, 2 days) or α-adrenergic receptor blockade with phentolamine did not alter the inhibitory effects of CGRP. We recently demonstrated that CCK stimulated the enteropancreatic neural pathways to mediate pancreatic secretion in rats with a chronic vagotomy. ICV-administered CGRP did not affect CCK-stimulated pancreatic secretion in rats with a chronic vagotomy. In conclusion, CGRP in the central nervous system inhibits pancreatic enzyme secretion stimulated by 2-DG and CCK-8, which act through vagal pathways. The inhibitory action of CGRP is not mediated by the sympathetic nervous system but appears to depend on intact vagus nerves.

Efficacy of octreotide (Octrade) for prevention of pancreatitis after endoscopic retrograde cholangiopancreatography

2020 ◽  
Vol 1 (30) ◽  
pp. 30-36
Author(s):  
E. A. Krylova ◽  
D. V. Aleinik
Keyword(s):  
Endoscopic Retrograde Cholangiopancreatography ◽  
Intravenous Infusion ◽  
Pancreatic Enzyme ◽  
Enzyme Secretion ◽  
Continuous Intravenous Infusion ◽  
Endoscopic Retrograde ◽  
Pancreatic Enzyme Secretion

The article presents the results of a study of the effectiveness of the use of an inhibitor of pancreatic enzyme secretion of octreotide (Octrade) for the prevention of pancreatitis after endoscopic retrograde cholangiopancreatography (ERCP). It was shown that the administration of Octrade at a dose of 0.3 mg in 500 ml of 0.9 % NaCl by continuous intravenous infusion for 7 hours and then 0.1 mg of Octrade subcutaneously at 6 and 12 hours after the end of intravenous infusion significantly reduced the frequency of pancreatitis (4.0 % and 22.2 %; p < 0.05) and hyperamylasemia (8.0 % and 25.9 %; p < 0.05) after ERCP. It is concluded that Octrade is effective in preventing the development of pancreatitis and hyperamilasemia after ERCP.

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