Effect of vagus nerve on the action potential duration of ventricular cell of dog I. Effect of stimulation of vagus nerve and atropine

Abstract

Action potentials of left ventricular cells were recorded intracellularly with floating glass microelectrode in dogs under α-chloralose anesthesia and spontaneous breathing.

The action potential duration (APD₉₀ and APD₅₀) of left ventricular cells was significantly prolonged from 129.8 ms to 136.4 ms and from 93.8 ms to 98.4 ms respectively (P < 0.01 in both) during stimulation of both cervical vagi.

After intravenous injection of atropine (0.03 mg/kg), the APD₉₀ and APD₅₀ of the left ventricular cells were shortened significantly from 133.8 ms to 127.1 ms and from 102.4 ms to 101.6 ms respectively (P < 0.001 andP < 0.0l), indicating a tonic effect of vagus nerve on the electrical activity of left ventricular cells.

The significance and mechanism of the above-mentioned prolongation and shortening of APDs are discussed.

Keywords

floating glass microelectrode / action potential duration of cardiac cell / vagal stimulation / atropine

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