L-type Ca(2+) channel blockers inhibit the development but not the expression of sensitization to morphine in mice.
The relationship between opioid actions and L-type Ca(2+) channel blockers has been well documented. However, there is no report relevant to L-type Ca(2+) channel blockers and morphine sensitization, which is suggested to be an analog of behaviors that are characteristic of drug addiction. We now studied systematically the effects of three L-type Ca(2+) channel blockers, nimodipine, nifedipine and verapamil, on morphine-induced locomotor activity, the development and the expression of sensitization to morphine. The results showed that both nimodipine and verapamil attenuated, while nifedipine had only a tendency to decrease morphine-induced locomotor activity. All three drugs inhibited the development of sensitization to morphine. However, none of them showed any effects on the expression of morphine sensitization. These results indicate that blocking L-type Ca(2+) channel attenuates the locomotor-stimulating effects of morphine and inhibits the development but not the expression of morphine sensitization.
Zhang
Qi
Q
Department of Neuropharmacology, National Institute on Drug Dependence, Peking University, 38 Xueyuan Road, Beijing 100083, PR China.
Li
Jun-Xu
JX
Zheng
Ji-Wang
JW
Liu
Rui-Ke
RK
Liang
Jian-Hui
JH
D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D020746:Calcium Channels, L-Type / Q000187:drug effects* / Q000502:physiology; D051379:Mice; D009020:Morphine / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects; D009292:Narcotic Antagonists / Q000494:pharmacology; D009294:Narcotics / Q000494:pharmacology*; D009543:Nifedipine / Q000494:pharmacology; D009553:Nimodipine / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology
D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D009292:Narcotic Antagonists; D009294:Narcotics; D009553:Nimodipine; D009020:Morphine; D014700:Verapamil; D009543:Nifedipine