1960 Volume 12 Issue 4 Pages 529-537
Electromyographic studies were made of effects of Spa and procaine on fibrillation voltage produced in chronically denervated tibialis anterior muscle of rabbit and on nociceptively as well as proprioceptively induced reflex discharges in tibialis anterior muscle of spinal and intact rabbit under non-anesthesia, to examine central or muscular actions of these drugs.
1) In small doses, Spa caused slight facilitation followed depression of spinal reflex discharges. The depressive effect was progressively pronounced until the discharges were completely eliminated.
Spa affected the spinal reflex activities more remarkably in intact rabbit by producing the excitatory action on brainstem reticular formation, than in spinal rabbit. In large doses, Spa caused depression of spinal reflex discharges soon after the administration of the drug in spinal as well as in intact rabbit.
Procaine had a somewhat similar action to Spa but differed from Spa in regard to the extent of excitative or depressive action. Spa was more potent than procaine in the effects on the spinal reflex discharges and the excitatory effect was revealed after the administration of procaine in the case of intact rabbit.
2) The fibrillation voltage in chronically denervated muscle increased following the administration of the small doses of Spa and in the lesser degree also following procaine. In large doses, both drugs caused depression of the fibrillation voltage. Spa may influence upon acetylcholine-potassium metabolism in degenerated muscle and also in the regulatory structure of the central nervous system.
