Isolated, blood-perfused phrenic nerve-diaphragm preparation of the XXXX : description of a new method and effects of neuromuscular blocking agents on twitch tension and blood flow.

@entity4485 @entity8427 @entity308 @entity3933 @entity235 @entity9563 @entity112 @entity2899 @entity2900
An isolated, blood-perfused phrenic nerve-diaphragm preparation of the @entity235 was developed for pharmacological investigation. A hemi-diaphragm with the ipsi-lateral phrenic nerve intact was excised from a @entity235 anesthetized with @entity4485 and was perfused with arterial blood from a donor @entity235 through the phrenic artery. This preparation maintained its tone and response in good condition for 10 hr without any deterioration of twitch tension. Effects of @entity2900 , @entity2899 , @entity8427 , and @entity9563 on twitch tension and blood flow of this preparation were studied. Drugs were injected into the phrenic artery. All four compounds produced a dose-dependent @entity308 of twitch tension elicited by indirect stimulation applied to the phrenic nerve without any @entity308 in the tension elicited by direct stimulation applied to the muscle. The ratios of the potency to produce a 50% @entity308 in twitch tension elicited by indirect stimulation among @entity2900 , @entity8427 , @entity2899 , and @entity9563 were roughly 1:1/3:1/3:1/30 on a weight (mg) basis. @entity2899 produced a dose-dependent increase in blood flow. Other compounds did not cause significant changes in blood flow. The increase in blood flow produced by @entity2899 was markedly inhibited by @entity3933 , which suggested @entity112 release by @entity2899 .
