Dopamine-dependent and dopamine-independent actions of cocaine as revealed by brain thermorecording in freely moving rats.

摘要: Brain temperature fluctuates biphasically in response to repeated, intravenous (i.v.) cocaine injections, perhaps reflecting cocaine's inhibiting effect on both dopamine (DA) transporters and Na + channels. By using a DA receptor blockade, one could separate these actions determine the role of DA-dependent DA-independent mechanisms mediating this fluctuation. Rats were chronically implanted with thermocouple probes brain, non-locomotor head muscle subcutaneously. Temperature fluctuations associated ten repeated i.v. injections (1 mg/kg 8-min inter-injection intervals) examined after combined, systemic administration selective D1-like D2-like blockers (SCH-23390 eticlopride) at doses that effectively inhibit transmission. In contrast initial increases subsequent biphasic (decreases followed by increases) seen saline-treated control, brain temperatures during blockade decreased each injection. had no effects skin temperature, which tonically fluctuated conditions. itself slightly increased temperatures, evident temperature. antagonists also strongly spontaneous movement activity completely blocked locomotor activation normally induced injections. Although our data confirm inhibitory action presynaptic uptake is essential for its ability induce metabolic behavioral activation, they suggest physiological drug cannot be explained through system alone. The continued hypothermic points other central systems (particularly channels) may important development abuse adverse drug.