Jackler F, Steiner S S, Bodnar R J, Ackermann R F, Nelson W T, Ellman S J
Int J Neurosci. 1979;9(1):21-35.
The purpose of this study was to examine if morphine, a drug of abuse, exerts site-specific effects on intracranial self-stimulation (ICSS). Rats, implanted with dorsal brainstem (DB) and hypothalamic (HYP) electrodes, bar-pressed for ICSS at two current intensities eight hours a day during six days each of predrug saline, morphine (2.5, 5.0, 7.5 or 10.0 mg/kg) and postdrug saline conditions. There were three patterns of drug effects: "pure" depressions, "pure" facilitations and a biphasic pattern (depressions followed by facilitations). Repeated morphine administration modified the temporal patterning of these effects: shortened duration of depressions and produced earlier onsets of facilitations. Within an animal, DB electrodes displayed more depressions than the HYP electrodes. Tolerance to the depressant effects, observed frequently, occurred occasionally to the facilitative effects of morphine. The drug effects on ICSS were dissociated from those observed on other behavioral measures, and thus are not artifacts of concomitant changes in activity levels.
本研究的目的是检验滥用药物吗啡是否对颅内自我刺激（ICSS）产生位点特异性效应。给大鼠植入脑桥背侧（DB）和下丘脑（HYP）电极，在给药前生理盐水、吗啡（2.5、5.0、7.5或10.0mg/kg）和给药后生理盐水条件下，大鼠每天8小时以两种电流强度按压杠杆进行ICSS，持续6天。药物效应有三种模式：“单纯”抑制、“单纯”促进和双相模式（先抑制后促进）。重复给予吗啡改变了这些效应的时间模式：缩短了抑制持续时间并使促进作用提前出现。在同一动物体内，DB电极显示出的抑制比HYP电极更多。经常观察到对吗啡抑制作用的耐受性，偶尔也会观察到对其促进作用的耐受性。吗啡对ICSS的药物效应与在其他行为指标上观察到的效应无关，因此不是活动水平伴随变化的假象。
