Electrophysiological Study on Effects of Activated Vitamin B₁ on the Movement of the Uterus

Abstract

An electrophysiological study was made with unanethetized rabbits of the effects of activated vitamin B₁ on the uterine movement and on the mechanism of analgetic effect in delivery.
1. The brain stem reticular formation was electrically stimulated at a rate of 100 c/s. Following the stimulation, the development of arousal reaction in EEG was accompanied with an accelerated uterine movement. Such acceleration seemed to be attributable to an accelerating action for the uterine movement given by mental activities due to an excitation of the ascending reticular activating system which is closely related with consciousness.
2. Contrary to the case with 100 c/s, electric stimulation at a rate of 3 c/s resulted in inhibition of uterine movement. Such inhibition seemed to be attributable to an added inhibitory action of uterine movement following a stimulation given to the inhibitory system due to different frequencies of stimuli on the brain stem reticular formation.
3. Administration of activated vitamin B₁ at a dosage of 0.2 - 2 mg/kg resulted in inhibition of arousal reaction which had developed in response to stimulation on the brain stem reticular formation. Uterine movement, however, revealed no acceleration whether or not stimuli were given to the brain stem reticular formation, following administration of the same dosage of activated vitamin B₁.
Arousal reaction results from the activi ties of the brain stem reticular formation and hippocampus. The development of consciousness is related with the brain stem reticular formation and that of pain with the hippocampus. It is concluded that the above results indicate that the analgesic mechanism of activated vitamin B₁ exists in the agent's inhibitory action of arousal reaction and that the agent at a dosage of 0.2 -2 mg/kg directly acts on the uterus to shorten a delivery time.