title: Studies on the excitatory neurotransmission in the guinea-pig urinary bladder.
abstract: The amplitude of atropine-resistant twich contractions of muscle strips of the guinea-pig urinary bladder was not changed after 90 min continuous electrical stimulation in the presence of 100 microM hemicholinium-3, as compared with the amplitude of the corresponding contractions in control experiments without hemicholinium-3. Addition of 100 microM choline to the medium did not change the amplitude of contractions either. Methionine-enkephalin (1 microM) known as a potent inhibitor of acetylcholine release in autonomic nerves did not change the amplitude of the twich responses. Apamin (1 microM) which inhibited the non-adrenergic, non-cholinergic responses in taenia coli did not change the amplitude of the atropine-resistant contractile responses of the guinea-pig urinary bladder. It is concluded that acetylcholine is not the principle excitatory neurotransmitter in the guinea-pig urinary bladder, although some cholinergic contribution to the twich response exists. The nonadrenergic, non-cholinergic atropine-resistant contractile response of the guinea-pig urinary bladder is apamin-resistant.
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D001030:Apamin / Q000494:pharmacology; D001414:Bacitracin / Q000494:pharmacology; D004558:Electric Stimulation; D004744:Enkephalin, Methionine / Q000494:pharmacology; D006145:Guanethidine / Q000494:pharmacology; D006168:Guinea Pigs; D006426:Hemicholinium 3 / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D012601:Scopolamine / Q000494:pharmacology; D009435:Synaptic Transmission / Q000187:drug effects; D013997:Time Factors; D001743:Urinary Bladder / Q000187:drug effects / Q000294:innervation / Q000502:physiology*
chemical_list: D001414:Bacitracin; D001030:Apamin; D006426:Hemicholinium 3; D004744:Enkephalin, Methionine; D000255:Adenosine Triphosphate; D012601:Scopolamine; D006145:Guanethidine