Canine galanin: sequence, expression and pancreatic effects

Mr, Boyle; Cb, Verchere; McKnight, Gary L.; Mathews, Sarah A.; Walker, Kendal; Gj, Taborsky

doi:10.1016/0167-0115(94)90185-6

Cited by 22 publications

(8 citation statements)

References 20 publications

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“…This raised the possibility that the potentiating action of galanin may involve suppression of somatostatin release. Galanin has been shown to inhibit somatostatin release (4,10). We found that preincubation with CAHP mimicked the effect of galanin on supramaximal caeruleinstimulated amylase secretion.…”

Section: Discussionmentioning

confidence: 68%

Galanin potentiates supramaximal caerulein-stimulated pancreatic amylase secretion via its action on somatostatin secretion

Barreto

Carati

Schloithe³

et al. 2009

American Journal of Physiology-Gastrointestinal and Liver Physi

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Barreto SG, Carati CJ, Schloithe AC, Toouli AC, Saccone GT. Galanin potentiates supramaximal caerulein-stimulated pancreatic amylase secretion via its action on somatostatin secretion. Am J Physiol Gastrointest Liver Physiol 297: G1268 -G1273, 2009. First published September 24, 2009 doi:10.1152/ajpgi.00342.2009.-Galanin inhibits pancreatic amylase secretion from mouse lobules induced by physiological concentrations of caerulein via an insulindependent mechanism. We aimed to determine the effect and elucidate the mechanism of action of exogenous galanin on pancreatic amylase secretion induced by supramaximal concentrations of caerulein. Amylase secretion from isolated murine pancreatic lobules was measured. Lobules were coincubated with galanin (10 Ϫ12 -10 Ϫ7 M) and caerulein (10 Ϫ7 M). Lobules were preincubated with atropine (10 Ϫ5 M), tetrodotoxin (10 Ϫ5 M), diazoxide (10 Ϫ7 M), or the galanin antagonist galantide (10 Ϫ12 -10 Ϫ7 M) for 30 min followed by incubation with caerulein alone, or combined with galanin (10 Ϫ12 M). Lobules were also coincubated with combinations of galanin (10, a somatostatin receptor antagonist (10 Ϫ9 M). Amylase secretion was expressed as percent of total lobular amylase. Caerulein stimulated amylase secretion to 124% of control. Diazoxide pretreatment abolished the caerulein-stimulated amylase secretion, whereas atropine or tetrodotoxin caused a partial inhibition. Galanin (10 Ϫ12 -10 Ϫ7 M) potentiated caerulein-stimulated amylase secretion to 160% of control. Preincubation with a combination of atropine and diazoxide abolished the potentiating effect of galanin, indicating muscarinic receptor and insulin mediation. Preincubation with galantide abolished the galanin effect, implying galanin receptor involvement. Coincubation with caerulein, galanin, and octreotide significantly reduced the potentiating effect galanin. However, coincubation with the somatostatin receptor antagonist, alone or in combination with galanin, significantly increased caerulein-stimulated amylase secretion to a level comparable to the galanin potentiation. Taken together, these data suggest that, at supramaximal caerulein concentrations, galanin acts via its receptors to further increase caerulein-stimulated amylase secretion by inhibiting the caerulein-induced release of somatostatin. pancreatic exocrine secretion; pancreatic lobules; cholinergic GALANIN IS A 29-AMINO ACID, COOH terminally amidated peptide that was first isolated by Tatemoto et al. (45) from the porcine intestinal mucosa. The 29-amino acid structure is common to most species, except humans, where it exists as a 30-amino acid molecule with no amidation at the NH 2 terminus. Galanin is involved in the regulation of numerous physiological functions, particularly in the central nervous and cardiovascular systems, and acts via three receptors designated as galanin receptors 1, 2, and 3 (13). Immunoreactivity for galanin has been localized in pancreatic nerves and also in a subset of islets (2, 5, 13). Galanin has variable effects on pancreatic...

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Section: Discussionmentioning

confidence: 68%

Galanin potentiates supramaximal caerulein-stimulated pancreatic amylase secretion via its action on somatostatin secretion

Barreto

Carati

Schloithe³

et al. 2009

American Journal of Physiology-Gastrointestinal and Liver Physi

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“…Immunoreactivity for galanin has been localized in pancreatic nerves and also in a subset of islets (2,10,35,116,121). Galanin inhibits secretion of insulin (103,109,116,121,174) and somatostatin (7,20). Ahren et al (3) were the first to study the effect of galanin on pancreatic exocrine secretion in isolated rat pancreatic acinar cells.…”

Section: Pancreatic Hormones and Neuropeptidesmentioning

confidence: 98%

The islet-acinar axis of the pancreas: more than just insulin

Barreto

Carati

Toouli³

et al. 2010

American Journal of Physiology-Gastrointestinal and Liver Physi

106

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Although the role of the islets in the regulation of acinar cell function seemed a mystery to investigators who observed their dispersion among pancreatic acini, over time an appreciation for this intricate and unique structural arrangement has developed. The last three decades have witnessed a steadily growing understanding of the interrelationship of the endocrine and the exocrine pancreas. The islet innervation and vascular anatomy have been more fully characterized and provide an appropriate background for our current understanding. The interrelationship between the endocrine and exocrine pancreas is mediated by islet-derived hormones such as insulin and somatostatin, other humoral factors including pancreastatin and ghrelin, and also neurotransmitters (nitric oxide, peptide YY, substance P, and galanin) released by the nerves innervating the pancreas. Although considerable progress has been achieved, further work is required to fully delineate the complex interplay of the numerous mechanisms involved. This review aims to provide a comprehensive update of the current literature available, bringing together data gleaned from studies addressing the actions of individual hormones, humoral factors, and neurotransmitters on the regulation of amylase secretion from the acinar cell. This comprehensive view of the islet-acinar axis of the pancreas while acknowledging the dominant role played by insulin and somatostatin on exocrine secretion sheds light on the influence of the various neuropeptides on amylase secretion.

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“…4). We found that treatment with 1 nM GnRH for 4,8,16, and 24 h increased galanin mRNA expression by 218%, 220%, 50%, and 40%, respectively (data not shown), suggesting a time-dependent GnRH effect on galanin expression in turtle pituitary. At 0.1-100 nM for 6 h of treatment, GnRH resulted in significant increases in the galanin mRNA, from 50 -1,500% ( Fig.…”

Section: Resultsmentioning

confidence: 88%

A preprogalanin cDNA from the turtle pituitary and regulation of its gene expression

Yu¹,

Pon²,

Ku³

et al. 2007

American Journal of Physiology-Regulatory, Integrative and Comp

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Galanin is a hormone 29 or 30 amino acids (aa) long that is widely distributed within the body and exerts numerous biological effects in vertebrates. To fully understand its physiological roles in reptiles, we analyzed preprogalanin cDNA structure and expression in the turtle pituitary. Using the Chinese soft-shell turtle (Pelodiscus sinensis order Testudines), we obtained a 672-base pair (bp) cDNA containing a 99-bp 5Ј-untranslated region, a 324-bp preprogalanin coding region, and a 249-bp 3Ј-untranslated region. The open-reading frame encoded a 108-aa preprogalanin protein with a putative 23-aa signal sequence at the NH 2 terminus. Based on the location of putative Lys-Arg dibasic cleavage sites and an amidation signal of Gly-Lys-Arg, we propose that turtle preprogalanin is processed to yield a 29-aa galanin peptide with Gly 1 and Thr 29 substitutions and a COOH-terminal amidation. Sequence comparison revealed that turtle preprogalanin and galanin-29 had 48 -81% and 76 -96% aa identities with those of other vertebrates, respectively, suggesting their conservative nature. Expression of the turtle galanin gene was detected in the pituitary, brain, hypothalamus, stomach, liver, pancreas, testes, ovaries, and intestines, but not in the adipose or muscle tissues, suggesting tissue-dependent differences. An in vitro study that used pituitary tissue culture indicated that treatment with 17␤-estradiol, testosterone, or gonadotropin-releasing hormone resulted in increased galanin mRNA expression with dose-or time-dependent differences, whereas leptin and neuropeptide Y reduced galanin mRNA levels. These results suggest a hormone-dependent effect on hypophyseal galanin mRNA expression.estrogen; androgen; gonadotropin-releasing hormone; neuropeptide Y; leptin GALANIN, a 29-amino acid (aa) hormone, was first isolated from porcine intestine and used to stimulate contractions of rat smooth muscle and to cause hyperglycemia in dogs (52). Since its discovery, galanin has also been found to exhibit numerous actions in vertebrates. For example, it induces feeding and the release of pituitary hormones [i.e., luteinizing hormone (LH) and growth hormone (GH)], decreases circulating levels of oxytocin, plays an antinociceptive role in the spinal cord, is involved in gastrointestinal motility and autonomic function, inhibits memory and learning, and promotes smooth muscle contractions (12). Moreover, clinical investigations have shown that galanin levels and galanin receptors are related to human disorders, such as Alzheimer disease and obesity (12). In reptiles, galanin can control gastrointestinal blood flow (24) and female oviposition (29). Although its mechanism of action in these reptilian physiological processes remains unknown, galanin in mammals reportedly operates via G i /G 0 -proteincoupled receptors involving effector systems such as K ϩ channels, Ca 2ϩ channels, and adenylate cyclase (3). In mice and humans, the galanin gene contains six exons and five introns (14, 26), and its mRNA consists of 398 -989 base pairs (bp),...

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Canine galanin: sequence, expression and pancreatic effects

Cited by 22 publications

References 20 publications

Galanin potentiates supramaximal caerulein-stimulated pancreatic amylase secretion via its action on somatostatin secretion

Galanin potentiates supramaximal caerulein-stimulated pancreatic amylase secretion via its action on somatostatin secretion

The islet-acinar axis of the pancreas: more than just insulin

A preprogalanin cDNA from the turtle pituitary and regulation of its gene expression

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