THE SHERRINGTON PHENOMENON

Abstract

IV. The Sherrington response renders the cat gastrocnemius refractory to subsequent stimulation of the nerve for about 10 sec. After 15 sec., it is partially refractory but gradually recovering its irritability. It does not fatigue the muscle to direct stimulation. Fatigue of the muscle by direct tetanization may produce complete, partial or no inhibition of the Sherrington response. Stimulation of the abdominal sympathetic trunk before or during the Sherrington contraction does not inhibit it. Stasis of the arterial blood supply does not prevent the occurrrence of the Sherrington phenomenon, in fact it may not inhibit it at all in the first 10 sec. Crystalline adrenalin (0.2 to 0.3 mgm. and 1.0 mgm.) inhibits, but not completely, the Sherrington response. Pilocarpine does not produce a contracture in denervated muscle, in fact it inhibits the Sherrington response. Atropine SO4 and Scopolamine HBr do not inhibit the Sherrington phenomenon. Curare inhibits it.[long dash]V. The Sherrington phenomenon in the quadriceps and gastrocnemius muscles of the cat is due to nerve impulses and not to spread or non-nervous conduction. It is not produced by conduction over somatic motor nerves coursing in an atypical manner. Antidromic conduction over somatic afferent fibers does not give an adequate explanation. It is produced by strong, rapid faradic stimulation of post-ganglionic sympathetic fibers. The possibilities of a humoral mechanism are discussed.