[Mechanisms of serotonin effect on motility of ileocaecal zone in alert rabbits].
I.V. administration of serotonin (2 mg kg(-1)) to alert rabbits changed the ileal, caecal, and colon motility including excitatory and inhibitory components. Initial rise of contractile activity was quickly replaced by its diminishing followed by a longer enhancement of the motility, and then by the final, inhibitory, phase. Under blockade of beta1- and beta2-adrenoreceptors with propranolol inhibition of ileal and caecal contractile activity with serotonin was preserved, the effect of circulating catecholamines on beta-adrenoreceptors of smooth muscle cells seems to be excluded as a cause of the serotonin inhibitory effect. In conditions of blockade of pre- and postsynaptic alpha-adrenoreceptors with phentolamine, there was no significant diminishing of the contractile activity in the ileo-caecal zone below the initial level induced by serotonin in control experiments. Intensification of the ileo-caecal zone contractile activity under the effect of serotonin persisted in conditions of blockade of muscarinic cholinoreceptors and was proceeding with participation of non-cholinergic excitatory mechanism.
Ovsiannikov
V I
VI
Berezina
T P
TP
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D018680:Cholinergic Antagonists / Q000494:pharmacology; D005769:Gastrointestinal Motility / Q000187:drug effects*; D007080:Ileocecal Valve / Q000187:drug effects* / Q000502:physiology; D007275:Injections, Intravenous; D011817:Rabbits; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects; D011943:Receptors, Adrenergic, beta / Q000187:drug effects; D011950:Receptors, Cholinergic / Q000187:drug effects; D012701:Serotonin / Q000008:administration & dosage / Q000494:pharmacology*; D014851:Wakefulness
D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D018680:Cholinergic Antagonists; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D011950:Receptors, Cholinergic; D012701:Serotonin