The nNOS expression in rat distal CSF contacting neurons and its relationship with morphine withdrawal / 中国药理学通报

ABSTRACT

Aim To observe the neuron nitric oxide synthase(nNOS) expression in the distal cerebrospinal fluid contacting neurons(CSF-CNs) of rat brain parenchyma, and investigate the role of CSF-CNs in the development of morphine dependence and withdrawal.Methods Male adult Sprague-Dawley rats, weighed 260?20 g,were experimented with A 3 ?l volume of 30% cholera toxin subunit B with horseradish peroxidase(CB-HRP) was injected into one of the rats′lateral ventricles to trace and locate the distal CSF-CNs of rat brain parenchyma 48 hours before the animals were killed. All animals were perfused and the relative tissue of rats′brain was removed.Frozen serial coronal sections (40 ?m) were cut. Then TMB-ST reaction procedure was used to stain the CB-HRP positive neurons,followed by immunohistochemistry double-labeling of the nNOS with CB-HRP positive neurons. The withdrawal symptoms were observed and scored. The numbers of the CB-HRP, and CB-HRP/nNOS positive neurons on the same segmental brain sections were counted.Results The withdrawal symptoms of the withdrawal group were significant, scores of all signs were significantly higher than those of the dependence groups and control group(P