Two cholecystokinin receptor subtypes are identified in goldfish, being the CCKAR involved in the regulation of intestinal motility.

Autor: Tinoco AB; Department of Physiology (Animal Physiology II), Faculty of Biology, University Complutense, Madrid (Spain)., Valenciano AI; Department of Physiology (Animal Physiology II), Faculty of Biology, University Complutense, Madrid (Spain)., Gómez-Boronat M; Department of Physiology (Animal Physiology II), Faculty of Biology, University Complutense, Madrid (Spain)., Blanco AM; Department of Physiology (Animal Physiology II), Faculty of Biology, University Complutense, Madrid (Spain)., Nisembaum LG; Department of Physiology (Animal Physiology II), Faculty of Biology, University Complutense, Madrid (Spain)., De Pedro N; Department of Physiology (Animal Physiology II), Faculty of Biology, University Complutense, Madrid (Spain)., Delgado MJ; Department of Physiology (Animal Physiology II), Faculty of Biology, University Complutense, Madrid (Spain). Electronic address: mjdelgad@bio.ucm.es.
Jazyk: angličtina
Zdroj: Comparative biochemistry and physiology. Part A, Molecular & integrative physiology [Comp Biochem Physiol A Mol Integr Physiol] 2015 Sep; Vol. 187, pp. 193-201. Date of Electronic Publication: 2015 Jun 05.
DOI: 10.1016/j.cbpa.2015.05.027
Abstrakt: Cholecystokinin (CCK) plays a key role in the digestive physiology of vertebrates. However, very little is known about the role of CCK on intestinal functions in fish. The present study identifies two CCK receptor subtypes in a stomachless teleost, the goldfish (Carassius auratus), and investigates by using an in vitro system their involvement mediating the effects of the sulfated octapeptide of CCK (CCK-8S) on the motility of isolated proximal intestine. Partial-length mRNAs encoding two CCK receptor isoforms (CCKAR and CCKBR.I) were sequenced and the structural analysis showed that both receptors belong to the G-protein coupled receptor superfamily. Both goldfish CCK receptor sequences were more closely related to zebrafish sequences, sharing the lowest similarities with cavefish and tilapia. The highest expression of goldfish CCKAR was observed along the whole intestine whereas the CCKBR gen was predominantly expressed in the hypothalamus, vagal lobe and posterior intestine. Application of CCK-8S to the organ bath evoked a concentration-dependent contractile response in intestine strips. The contractions were not blocked by either tetrodotoxin or atropine, suggesting that CCK-8S acts on the gut smooth muscle directly. Preincubations of intestine strips with devazepide and L365,260 (CCKAR and CCKBR receptor selective antagonists) showed that the CCK-8S-induced contraction could be partially mediated by the CCKAR receptor subtype, which is also the most abundant CCK receptor found in gastrointestinal tissues. In conclusion, two CCK receptors with a differential distribution pattern has been identified in goldfish, and the CCKAR subtype is mainly involved in the regulation of intestinal motility by the CCK-8S.
(Copyright © 2015 Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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