[The role of different mechanisms of cholinergic regulation in controlled bradycardia evoked by vagal stimulation].
In experiments on anesthetised cats we investigated functional significance of different cholinergic mechanisms regulating the magnitude of vagal chronotropic effect components, inhibitory tonic and synchronizing. It was established that inhibitory tonic vagal component is determined by intensity of acetylcholine hydrolysis and total amount of excited cardiac M-cholinoreceptors. The magnitude of synchronizing vagal component depended on subtypes of cholinoreceptors selectively excited by acetylcholine released from vagal terminals. In particular, the blockade of M1- or M3-cholinoreceptors potentiated the synchronizing vagal component, whereas the blockade of M2-cholinoreceptors inhibited it.
Osadchiĭ
O E
OE
Normal Physiology Dept., Kuban Medical Academy, Russia.
Pokrovskiĭ
V M
VM
D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D002415:Cats; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D003864:Depression, Chemical; D004558:Electric Stimulation; D004562:Electrocardiography; D006339:Heart Rate / Q000187:drug effects; D018727:Muscarinic Antagonists / Q000494:pharmacology; D043643:Receptor, Muscarinic M1; D043585:Receptor, Muscarinic M2; D043587:Receptor, Muscarinic M3; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000502:physiology*; D014630:Vagus Nerve / Q000502:physiology*
D002800:Cholinesterase Inhibitors; D018727:Muscarinic Antagonists; D043643:Receptor, Muscarinic M1; D043585:Receptor, Muscarinic M2; D043587:Receptor, Muscarinic M3; D011976:Receptors, Muscarinic; D000109:Acetylcholine