[Action of enkephalins on synaptic processes in the metasympathetic nervous system].
Experimental data were obtained on the effect of leu- and metenkephalin solutions (0.01-10.0 micrograms) on spontaneous responses and those evoked by transmural stimulation of the neural structures in the neuro-muscular preparation which included the myenteric plexus and circular smooth muscle layer. The observed excitatory action of enkephalins involving depolarization of the smooth muscle cell membrane, the increase of spontaneous AP frequency, reduced amplitude of the evoked ISP, increased voltage and intensified contractile activity of the preparation are related to participation of the opiate receptors. (Naloxone administration abolished the enkephalin effects). Application of alpha- and beta-adrenergic blocking drugs failed to change the type of their action. Enkephalin effects were most pronounced at low frequency stimulation and were not observed in the solution containing both M- and N-cholinergic blocking drugs. Enkephalins seem to participate in the mechanisms of descending tonic control of the smooth muscle activity maintained by non-adrenergic, non-cholinergic motor neurons.
D000818:Animals; D004558:Electric Stimulation; D004745:Enkephalins / Q000494:pharmacology*; D005071:Evoked Potentials / Q000187:drug effects; D006168:Guinea Pigs; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D009270:Naloxone / Q000494:pharmacology; D009469:Neuromuscular Junction / Q000187:drug effects; D011957:Receptors, Opioid / Q000187:drug effects; D013564:Sympathetic Nervous System / Q000187:drug effects*; D013565:Sympatholytics / Q000494:pharmacology; D013569:Synapses / Q000187:drug effects*; D013779:Tetrodotoxin / Q000494:pharmacology
D004745:Enkephalins; D011957:Receptors, Opioid; D013565:Sympatholytics; D009270:Naloxone; D013779:Tetrodotoxin
Issledovanie deĭstviia énkefalinov na sinapticheskie protsessy v metasimpaticheskoĭ nervnoĭ sisteme.