Depolarization-induced release of propranolol and atenolol from rat cortical synaptosomes.

摘要: The accumulation and release of [3H]-propranolol [3H]-atenolol were examined in synaptosomes from rat cerebral cortex. Synaptosomes accumulated 20 pmol propranolol 0.6 atenolol mg-1 protein when incubated at 30 degrees C with radiolabelled drugs (0.1 microM). Exposure propranolol-loaded to elevated K+, Rb+ or Cs+ evoked a concentration-dependent increase efflux. action these ions releasing was highly correlated their ability produce synaptosomal membrane depolarization, as estimated the voltage-sensitive dye diS-C3-(5). Elevated K+ also promoted manner. Veratridine (10 microM) released effects antagonized by tetrodotoxin (1 Under Ca2+-free conditions, K+-induced reduced 37% diminished 68%. results support concept that both polar non-polar beta-adrenoceptor blocking may be nerve endings for depolarization suggest neural storage molecules influence concentrations localized sites action.