[Mechanism of inhibition of the contractile activity in the jejunum and ileum under psychogenic stress in rabbits].
In chronic experiments on rabbits, myoelectric activity (contractile activity index) in proximal and distal part of the jejunum and proximal part of the ileum was studied under psychogenic stress caused by rigid fastening of the rabbit to table in supine position. Inhibition of contractile activity in the proximal and distal parts of thejejunum in the 1st phase of the stressor response manifested on the background of blockade of presynaptic alpha 2-adrenoceptor with yohimbin, nonselective blockade of alpha-adrenoceptor with dihydroergotoxin, or blockade of beta 1/beta 2-adrenoceptor with propranolol. Conclusion is made that the stressor inhibition of contractile activity in the proximal and distal parts of the jejunum was not "adrenergic cholinergic" or "adrenergic" in origin. The contractile activity inhibition of the jejunum was actualized with the contribution of "nonadrenergic noncholinergic" inhibitory mechanism and mediated via nonadrenergic inhibitory neurons of the enteric nervous system. Depression of the contractile activity in the proximal part of ileum being preserved after blockade of presynaptic "alpha 2-adrenoceptor" or blockade of beta 1/beta 2-adrenoceptor, was not "adrenergic cholinergic" or "beta-adrenergic". Nonselective blockade of alpha-adrenoceptor resulted in diminished stressor inhibition of the contractile activity in the proximal part of ileum. The data obtained suggest that the stressor inhibition of the contractile activity in the proximal part of ileum was caused by "nonadrenergic noncholinergic" inhibitory mechanism with participation of the "alpha-adrenergic" inhibition. The "nonadrenergic noncholinergic" inhibition of the contractile activity in the jejunum and ileum might result from activation of enteric inhibitory neurons with a stressor factor of hormonal nature.
Berezina
T P
TP
Ovsiannikov
V I
VI
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D017615:Enteric Nervous System / Q000502:physiology; D005769:Gastrointestinal Motility / Q000502:physiology; D007082:Ileum / Q000294:innervation / Q000378:metabolism / Q000503:physiopathology*; D007583:Jejunum / Q000294:innervation / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D009130:Muscle, Smooth / Q000378:metabolism / Q000503:physiopathology*; D009474:Neurons / Q000378:metabolism / Q000502:physiology; D011817:Rabbits; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism; D011943:Receptors, Adrenergic, beta / Q000378:metabolism; D012149:Restraint, Physical; D013315:Stress, Psychological / Q000503:physiopathology*
D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta