[Oxidative phosphorylation in different regions of the rat brain following morphine administration]

The influence exercised by morphine in a dose of 20 mg/kg, introduced intraperitoneally, and also in concentrations of 10(-3) and 10(-5) "in vitro" on the parameters of oxidative phosphorylation of the brain cortex and stem of rats was studied. Morphine, used in a concentration of 10(-3), is shown to speed up the substrates oxidation rate. During the first days of its administration the narcotic analgetic inhibited oxidation of mitochondia released from the brain stem, and, once habituation to the narcotic had developed, the inhibition ceased to be effective. In "in vivo" experiments and in vitro tests the effect of phosphorylation remained unchanged. The data obtained suggest that with developing habituation in regard to morphine the functions of the brain stem and cortex mitochondria do not undergo any substantial changes.