Synergism of physostigmin with acetylcholin, though it might be ascribed to anticholinesterase action of the former, was pursuited with the heart of
Bufo vulgaris japonicus. The administration of physostigmin, as compared with no administration of the drug, resulted in the appearance of the more remarkable cardio-inhibitory effect upon the
in vivo self-blood-circulating heart and the iso-lated or the in vivo heart, both being perfused, whose vagus or sympathetic nervous fibres were suffering the electric stimulus. There were seasonal variations in the degree of this action, strong in winter and weak in spring or fall. Physostigmin may possibly promotes excitability of cardio-sympathetic nervous endings, though not so distinct in cardio-sympathetic nervous endings as in vagus, but appreciated by the increased heart beats produced by the electric stimulus to sympathetic or vagosympathetic nerves while the drug be acting. This promotion of heart beats by physostigmin was subjected to seasonal variations and most sinificant in spring or summer. Physostigmin, when given to the heart perfused by. fresh
Ringer's solution for a long time, brought about the remarkable Increase of heart beats which was not observed before perfusion. This may be possibly attributable to the excitement of sympathetic nervous endings by physostigmin.
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