CALCIUM DEPLETION OF SYNAPTOSOMES AFTER MORPHINE TREATMENT

Abstract
1 It was confirmed that morphine administration in vivo produced a selective decrease in the calcium content of synaptosomal fractions prepared from rat cerebral cortices. This effect was prevented by naloxone. 2 After morphine or naloxone, there were no changes in the sodium, potassium and magnesium contents of any of the seven subcellular fractions tested. 3 Since the selective calcium loss was found to occur from fractions similar to those reported to exhibit opiate receptor binding, it is concluded that calcium may play a role in the action of narcotic agonist drugs.