caa a22 4500 477117457 CHVBK 20180405111626.0 cr unu---uuuuu 170330e19960401xx s 000 0 eng 10.1007/BF01875589 doi (NATIONALLICENCE)springer-10.1007/BF01875589 Effects of modulatory agents on neurally-mediated responses of trout intestinal smooth muscle in vitro [Elektronische Daten] [John Burka, Heather Briand, Cheryl Wartman, Jeffrey Hogan, William Ireland] Mediators and mechanisms responsible for the inhibitory modulation of trout intestinal smooth muscle were examined using a series of putative mediators and substances known to modulate neurotransmission in mammalian systems. Frequency response relationships to transmural stimulation and concentration response relationships to 5-hydroxytryptamine, carbachol, and substance P were established on paired segments of rainbow trout intestinein vitro in the presence and absence of putative modulatory agents. Modulation of neurally-mediated contractions of trout intestine was achieved with dibutyryl cyclic AMP and forskolin, agents that increase intracellular levels of cyclic AMP. The effect appears to be at the level of the smooth muscle, since the adenylate cyclase activator, forskolin, inhibited muscarinic and serotoninergic contractions as well as transmurally stimulated contractions. Substance P-induced contractions were unaffected by forskolin. The endogenous agonists/neurotransmitters which would increase cyclic AMP levels in rainbow trout intestinal smooth muscle are as yet unknown. The effects do not appear to be modulated by vasoactive intestinal peptide (VIP), calcitonin, calcitonin gene-related peptide (CGRP), or agents that activate β-adrenoceptors. Prostaglandin E2 (PGE2) and α2-adrenergenic agonists are possible agents which will decrease contractility of the smooth muscle. They were only active in the proximal intestine and on transmurally stimulated contractions. The effects of both PGE2 and α2-agonists appear to be prejunctional, decreasing release of contractile neurotransmitters in the enteric nervous system. Kugler Publication bv Amsterdam, 1996 rainbow trout nationallicence intestine nationallicence smooth muscle nationallicence neurotransmission nationallicence modulators nationallicence α-adrenergic receptors nationallicence cyclic AMP nationallicence Burka John Department of Anatomy and Physiology, Atlantic Veterinary College, University of Prince Edward Island, C1A 4P3, Charlottetown, P.E.I. aut Briand Heather Department of Anatomy and Physiology, Atlantic Veterinary College, University of Prince Edward Island, C1A 4P3, Charlottetown, P.E.I. aut Wartman Cheryl Department of Anatomy and Physiology, Atlantic Veterinary College, University of Prince Edward Island, C1A 4P3, Charlottetown, P.E.I. aut Hogan Jeffrey Department of Anatomy and Physiology, Atlantic Veterinary College, University of Prince Edward Island, C1A 4P3, Charlottetown, P.E.I. aut Ireland William Department of Anatomy and Physiology, Atlantic Veterinary College, University of Prince Edward Island, C1A 4P3, Charlottetown, P.E.I. aut Fish Physiology and Biochemistry Kluwer Academic Publishers 15/2(1996-04-01), 95-104 0920-1742 15:2<95 1996 15 10695 https://doi.org/10.1007/BF01875589 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF01875589 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Burka John Department of Anatomy and Physiology, Atlantic Veterinary College, University of Prince Edward Island, C1A 4P3, Charlottetown, P.E.I aut NATIONALLICENCE 700 1- Briand Heather Department of Anatomy and Physiology, Atlantic Veterinary College, University of Prince Edward Island, C1A 4P3, Charlottetown, P.E.I aut NATIONALLICENCE 700 1- Wartman Cheryl Department of Anatomy and Physiology, Atlantic Veterinary College, University of Prince Edward Island, C1A 4P3, Charlottetown, P.E.I aut NATIONALLICENCE 700 1- Hogan Jeffrey Department of Anatomy and Physiology, Atlantic Veterinary College, University of Prince Edward Island, C1A 4P3, Charlottetown, P.E.I aut NATIONALLICENCE 700 1- Ireland William Department of Anatomy and Physiology, Atlantic Veterinary College, University of Prince Edward Island, C1A 4P3, Charlottetown, P.E.I aut NATIONALLICENCE 773 0- Fish Physiology and Biochemistry Kluwer Academic Publishers 15/2(1996-04-01), 95-104 0920-1742 15:2<95 1996 15 10695 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer