Effects of Ketamine and Morphine on the Changes of Brain Catecholamine Concentration in Mice

Keimyung Medical Journal 1990;9(1):61-70.

뇌조직 Catecholamine 함량 변동에 미치는 Ketamine 및 Morphine의 영향

김수경

Abstract

There are many reports that ketamine-induced analgesia is prevented by narcotic receptor antagonist; naloxone. Neurochemically; ketamine has been shown to interact with opioid receptor and may increase neuronal activity in the monoaminergic systems in the manner similar to morphine. However; other evidence indicates that ketamine has negligible affinity for specific opioid receptors and its analgesic effects. In the light of these conflicting findings; the purpose of the present study was to compare changes of brain concentration of catecholamine(norepinephrine and dopamine) in response to naloxone; clonidine; yohimbine and prazosin in single ketamine(20mg/kg) or morphine(10mg/kg) and chronic ketamine(AM:10 PM:5; twice in a day; 20mg/kg for lOdays) or morphine(AM:10 PM:5; twice in a day; lOmg/kg for lOdays) treatment in mice. The results obtained are summarized as follows: 1. The concentration of NE was decreased significantly in 30 min. and that of dopamine was decreased significantly in 30;60 and 120 min. by a single ketamine treatment. The concentrations of NE and dopamine were not affected by chronic ketamine treatment. 2. The concentration of NE was decreased significantly in 30 min. and that of dopamine was decreased significantly in 30 min. and 60 min; by a single morphine treatment. The concentration of dopamine was decreased significantly by chronic morphine treatment. 3. The concentrations of NE and dopamine were not affected by administrations of naloxone or clonidine; but those of NE and dopamine were decreased significantly by yohimbine in chronic ketamine treated group. 4. The concentration of NE was not affected by naloxone or clonidine or yohimbine or prazosin;but that of dopamine was increased by naloxone or clonidine and not affected by yohimbine or prazosin in chronic morphine treated group.