Response of the A-V node of the rabbit to stimulation of intracardiac cholinergic nerves.

Content Provider	Semantic Scholar
Author	West, T. C. Toda, Noboru
Copyright Year	1967
Abstract	The cholinergic innervation of the rabbit heart was studied in vitro and in vivo. An isolated preparation, which included the combined atria, S-A node, A-V node and bundle of His, was mounted so that microelectrodes could be placed in either the specialized or nonspecialized tissues. Using a roving monopolar electrode, local transmural electrical stimulation of intracardiac nerves (nerve stimulation) was applied at the A-V or the S-A node. At the A-V node it induced hyperpolarization, reduced the duration and amplitude of action potentials recorded from three regions of die A-V node and the His bundle, whether the preparation was spontaneously beating or electrically driven in either the forward or retrograde direction, and blocked membrane excitation in the nodal and nodal-His regions and to downstream structures. The depressant effects of nerve stimulation were augmented by physostigmine and antagonized by atropine. Addition of acetylcholine to die bath reduced the frequency at which the A-V node conducted, but in the concentrations used did not duplicate the effects of nerve stimulation. The behavior of the S-A node is qualitatively similar to that of the A-V node. In the presence of a sinus rhythm, nerve stimulation applied at the A-V node did not affect the activity of the S-A node, and during artificial atrial drive, nerve stimulation of the S-A node did not affect A-V nodal function, indicating that little or no neural communication exists between the two regions in die isolated preparation. Locally released acetylcholine appears to depress excitability of specialized cells in the central node, independently of the direction of propagation. ADDITIONAL
Starting Page	18
Ending Page	31
Page Count	14
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PubMed reference number	6018221v1
Volume Number	20
Issue Number	1
Journal	Circulation research
Language	English
Access Restriction	Open
Subject Keyword	Acetylcholine Action Potentials Anatomic Node Atropine Body tissue Bundle of His Celiac lymph node Electric stimulation technique Electricity Excitation Heart Atrium Heart valve disease In Vitro [Publication Type] Nerve Tissue Olfactory Nerve Physostigmine Sinoatrial Node Sinus - general anatomical term Tissue membrane nerve supply
Content Type	Text
Resource Type	Article