[Effects of electrical stimulation of the dorsal cutaneous branches of spinal nerves on the discharge activity of remote mechanoreceptive units in rats].

The method of isolating filaments of the dorsal cutaneous branches was used to observe the effects of antidromic electrical stimulation of the spinal nerves on the discharge of remote A delta and C mechanoreceptive units in rats. Seventy-nine mechanoreceptive units were recorded from the T12 nerve filaments after stimulation of the dorsal cutaneous branches of T9 spinal nerve. It was found that the discharge frequency of 59.3% (16/27) A delta-units and 71.2% (37/52) C-units significantly increased during 90-120 s after the stimulation. Sixty-four mechanoreceptive units were recorded from the T12 nerve filaments after stimulation of the dorsal cutaneous branches of T8 spinal nerves. The discharge frequency of 47.8% (11/23) A delta-units and 36.6% (15/41) C-units significantly increased during 120-150 s after the stimulation. In addition, the threshold of the majority of these mechanoreceptors (78.3%, 18/23) decreased after the stimulation. The results suggest that antidromic electrical stimulation of the dorsal cutaneous branches of spinal nerves leads to sensitization of A delta and C mechanoreceptive units of the remote peripheral nerve endings, which results in an increase in afferent discharge of these units.