beta-adrenoceptor blockade with diphenylhydantoin (DPH).
Diphenylhydantoin (DPH) (20 x 10(-6) to 80 x 10(-6) M/kg) blocked the depressor responses to isoproterenol in spinal, bilaterally vagotomized and atropine pretreated cats; depressor responses to histamine were unaffected; DPH shifted the isoproterenol concentration-response curve to the right in isolated guinea pig tracheal chain preparation, isolated rabbit ileum and isolated perfused heart of frog. The results suggest that DPH has a specific beta-adrenoceptor blocking action and the blockade appears to be competitive in nature as shown by PA2 and PA10 values.
beta-adrenoceptor blockade with diphenylhydantoin (DPH). Diphenylhydantoin (DPH) (20 x 10(-6) to 80 x 10(-6) M/kg) blocked the depressor responses to isoproterenol in spinal, bilaterally vagotomized and atropine pretreated cats; depressor responses to histamine were unaffected; DPH shifted the isoproterenol concentration-response curve to the right in isolated guinea pig tracheal chain preparation, isolated rabbit ileum and isolated perfused heart of frog. The results suggest that DPH has a specific beta-adrenoceptor blocking action and the blockade appears to be competitive in nature as shown by PA2 and PA10 values.