RT Journal Article
SR Electronic
T1 THE EFFECT OF 6-HYDROXYDOPAMINE ON MORPHINE TOLERANCE AND PHYSICAL DEPENDENCE
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 49
OP 55
VO 183
IS 1
A1 GLADYS FRIEDLER
A1 HEMENDRA N. BHARGAVA
A1 RAYMOND QUOCK
A1 E. LEONG WAY
YR 1972
UL http://jpet.aspetjournals.org/content/183/1/49.abstract
AB The effect of 6-hydroxydopamine (6-OHDA), which is known to deplete selectively catecholamines by destruction of catecholaminergic neurons, was investigated in mice rendered tolerant to and dependent upon morphine by pellet implantation. Pretreatment with 6-OHDA intracerebrally with a dose that caused 66 and 30% depletion of norepinephrine and dopamine, respectively, reduced the analgetic response of morphine (AD50) in both tolerant and nontolerant mice without modifying the brain uptake of morphine. The relative increase in morphine AD50 in both groups was approximately the same, and it was concluded that 6-OHDA affects the acute response to morphine but not the process primarily involved in initiating the development of tolerance to morphine. Precipitated abstinence, as measured by naloxone-induced withdrawal jumping was enhanced by 6-OHDA pretreatment; weight loss after abrupt withdrawal was also increased by 6-OHDA. The possibility that catecholamines may be involved in the stereotyped withdrawal jumping behavior observed in morphine-dependent mice is suggested. © 1972, by The Williams & Wilkins Company