Reversible Conduction Block in Peripheral Mammalian Nerve Using Low Frequency Alternating Current^*

摘要

Activation of nerve fibers using electricity has been known since antiquity. Methods to block propagating action potentials (AP) are a more recent discovery. This paper describes a method to reversibly block nerve conduction using a low frequency (1 Hz) alternating current (LFACb) waveform. An in situ electrophysiology setup was used to assess the LFACb on propagating APs within the cervical vagus nerve in six anaesthetized Sprague-Dawley rats. Two sets of Pt-Ir hook electrodes were used. The rostral electrode was used to generate a volley of APs while the LFACb waveform was presented to the caudal electrode. This efferent volley, if unblocked, elicits acute bradycardia and hypotension. Block was assessed by ability to reduce this bradycardic drive by monitoring the heart rate (HR) and blood pressure (BP) during LFACb alone, LFACb and vagal stimulation, and vagal stimulation alone. Using the LFACb technique, 82 ± 15% conduction block was achieved with current levels 100 ± 36 μA_p.