Premium
Role of galanin receptor 1 in gastric motility in rat
Author(s) -
Guerrini S.,
Raybould H. E.,
Anselmi L.,
Agazzi A.,
Cervio E.,
Reeve J. R.,
Tonini M.,
Sternini C.
Publication year - 2004
Publication title -
neurogastroenterology and motility
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.489
H-Index - 105
eISSN - 1365-2982
pISSN - 1350-1925
DOI - 10.1111/j.1365-2982.2004.00534.x
Subject(s) - galanin , motility , endocrinology , medicine , galanin receptor , inhibitory postsynaptic potential , excitatory postsynaptic potential , nitric oxide , receptor , nitric oxide synthase , tetrodotoxin , chemistry , vasoactive intestinal peptide , neuropeptide , biology , microbiology and biotechnology
Galanin actions are mediated by distinct galanin receptors (GAL‐R), GAL‐R1, ‐R2 and ‐R3. We investigated the role of GAL‐R1 in gastric motility and the expression of GAL‐R1 in the rat stomach. In vivo , in urethane‐anaesthetized rats, galanin (equipotent for all GAL‐Rs) induced a short inhibition of gastric motility, followed by increase in tonic and phasic gastric motility; the latter was significantly reduced by the GAL‐R1 antagonist, RWJ‐57408. Galanin 1–16 (high affinity for GAL‐R1 and ‐R2) induced a long‐lasting decrease of intragastric pressure, which was not modified by RWJ‐57408. In vitro , galanin and galanin 1–16 induced increase of intragastric pressure that was not affected by RWJ‐57408. Tetrodotoxin (TTX) did not suppress the galanin excitatory effect, whereas the effect of galanin 1–16 on gastric contraction was increased by TTX‐ or N‐nitro‐L‐arginine, an inhibitor of nitric oxide synthase. GAL–R1 immunoreactivity was localized to cholinergic and tachykinergic neurons and to neurons immunoreactive for nitric oxide synthase or vasoactive intestinal polypeptide. This study suggests that an extrinsic GAL‐R1 pathway mediates the galanin excitatory action, whereas an extrinsic, non GAL‐R1 pathway is likely to mediate the galanin inhibitory effect in vivo . GAL‐R1 intrinsic neurons do not appear to play a major role in the control of gastric motility.