Distribution of TRPC6 in the cerebrospinal fluid-contacting nucleus of rat brain parenchyma and its expression in morphine dependence and withdrawal.

To investigate the role of cerebrospinal fluid contacting nucleus (CSF-CN) and the changes of TRPC6 expression in morphine dependence and withdrawal. Male Sprague-Dawley rats (250 ± 50 g) were randomly divided into four groups: the normal group (N); the saline group (S); the morphine dependence group (D); the morphine withdrawal group (W). All animals in each group were tested the morphine withdrawal-like behavioral signs by total withdrawal scores. Double-labeled immunofluorescent technique and laser scanning confocal microscopy were used to identify the expression of TRPC6 in CSF-CN. TRPC6 labeled neurons were found in CSF-CN and the number of CB-HRP/TRPC6 double labeled neurons in CSF-CN significantly increased. TRPC6 existed in CSF-CN of the normal rats and its expression in morphine dependence and withdrawal increased. CSF-CN might participate in the development of morphine dependence and withdrawal by the up-regulated expression of TRPC6.