Effects of neurotensin on the non-adrenergic inhibitory neurotransmission in the guinea-pig duodenum.
The effects of neurotensin on the non-adrenergic inhibitory neurotransmission in the guinea-pig duodenum were investigated. The resting membrane potential of the duodenal smooth muscle cells was reduced by neurotensin at the concentration of 3 X 10(-8) M or more. The amplitude of the non-adrenergic inhibitory potentials was decreased by neurotensin (1-3 X 10(-8) M). In the Ca2+-free solution, the amplitude of the inhibitory potentials was also decreased. The increased amplitude of the non-adrenergic inhibitory potentials evoked in the high calcium solution (Ca2+, 5 mM) was decreased by neurotensin (10(-8) M). Neither atropine (1.4 X 10(-6) M) nor propranolol (3.4 X 10(-6) M) blocked the inhibitory action of neurotensin (10(-8) M) on the inhibitory potential. The frequency of the spontaneous action potentials of the duodenal smooth muscle cells was strongly increased with accompanying depolarization by neurotensin 8 X 10(-8) M. The tonic contraction of the duodenal smooth muscles was produced by neurotensin (3-8 X 10(-8) M). The results obtained suggest that neurotensin relates to the non-adrenergic inhibitory pathway in the control mechanism on intestinal motility.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001285:Atropine / Q000494:pharmacology*; D002118:Calcium / Q000494:pharmacology; D004386:Duodenum / Q000187:drug effects / Q000294:innervation* / Q000502:physiology; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000294:innervation* / Q000502:physiology; D009496:Neurotensin / Q000494:pharmacology*; D011433:Propranolol / Q000494:pharmacology*; D009435:Synaptic Transmission / Q000187:drug effects*
D009496:Neurotensin; D001285:Atropine; D011433:Propranolol; D002118:Calcium