Real time detection of acute (IP) cocaine-enhanced dopamine and serotonin release in ventrolateral nucleus accumbens of the behaving Norway rat.
Cocaine (10 mg/kg), administered intraperitoneal (IP), was studied for its effects on dopamine (DA) and serotonin (5-HT) release in ventrolateral nucleus accumbens (vlNAcc) of conscious and behaving male, virus-free, Sprague-Dawley rats with in vivo electrochemistry (voltammetry). Miniature stearate probes detected DA and 5-HT release, on line and within a temporal resolution of seconds. Psychostimulant behaviors, in the form of four behavioral components (i.e., the classically DA-dependent behaviors of locomotor activity [ambulations], rearing, and stereotypy, and a 5-HT-ergic behavior, central ambulations) were studied concurrently with infrared photobeam detection. The results show that (IP) cocaine significantly increased vlNAcc DA release (p < 0.0001) and 5-HT release (p < 0.0012). Each of the four parameters of cocaine-induced psychostimulant behavior was concurrently and significantly increased as well (ambulations: p < 0.0001); rearing p < 0.0008; stereotypy: p < 0.0004; central ambulations: p < 0.0082). Moreover, exactly coincident data points for DA and 5-HT release occurred 10 and 40 min after (IP) cocaine administration. Cocaine-induced DA and 5-HT release were highly and positively correlated during the first hour of study (p < 0.01). As expected, increased DA release in vlNAcc after cocaine administration was significantly and positively correlated with classically DA-dependent behaviors (first- and second-hour effects) (p < 0.01) and with the 5-HT-ergic behavior, central ambulations (p < 0.01). Also, cocaine-induced 5-HT release was significantly and positively correlated with 5-HT behavior (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
Broderick
P A
PA
Department of Pharmacology, City University of New York Medical School, NY 10031.
Kornak
E P
EP
Eng
F
F
Wechsler
R
R
D000818:Animals; D001007:Anxiety / Q000523:psychology; D003042:Cocaine / Q000008:administration & dosage / Q000494:pharmacology*; D004298:Dopamine / Q000378:metabolism*; D004563:Electrochemistry; D007274:Injections, Intraperitoneal; D008297:Male; D008839:Microelectrodes; D009714:Nucleus Accumbens / Q000033:anatomy & histology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism*; D013569:Synapses / Q000187:drug effects / Q000378:metabolism
D012701:Serotonin; D003042:Cocaine; D004298:Dopamine