Possible role of certain neurotransmitters of the monoamine type on butorphanol tartrate-induced physical dependence in mice

ABSTRACT

Brain monoamines were spectrophotofluorometrically determined during the appearance of butorphanol tartrate withdrawal symptoms in addict adult male mice. The animals were rendered addict by daily administration of the drug for 12 successive days in gradually increasing doses, starting from 1mg/kg and up to 15 mg/kg body weight. Such animals when deprived from butorphanol tartrate, showed after 24 hours severe syndrome consisting of writhing, teeth chattering, ptosis, tachycardia, tremors, and marked nervous hyperexcitability. The animals were decapitated at that time for the determination of their brain contents of dopamine, norepinephrine and serotonin. Compared with a parallel group injected with normal saline and used as control, there was a significant increase in dopamine and norepinephrine contents in brain amounting to 53 and 220%, respectively. On the other hand, no change in brain serotonin content was observed. The results of this work point to a probable role for brain dopamine and norepinephrine but not for serotonin on the induction of butorphanol tartrate withdrawal symptoms in addict adult male mice