Effects of morphine-dependent and withdrawal on activation of the distal cerebrospinal fluid contacting neurons' phosphorylation CREB in rat brain

Abstract

Objective: To investigate the changes of pCREB protein expression in the distal cerebrospinal fluid contacting neurons induced by chronic morphine dependence and withdrawal.Methods: Twenty-four Sprague–Dawley rats of both genders were randomly divided into three groups (n=8 each): control (Group I); chronic morphine dependence (Group II); chronic morphine abstinence (Group III). Chronic morphine dependence was induced by increasing doses of morphine, starting from 5 to 260 mg/kg/day in 12 days. The animals were killed 24 hours later. We evaluated morphine dependence by measuring the behavioral expression of morphine withdrawal and pCREB double labeled neuron recordings of dorsal raphe nucleus. The CB-HRP/pCREB double labeling method was used to observe the expression of pCREB in the distal cerebrospinal fluid contacting neurons.Results: The results showed the number of double labeled neuron of distal cerebrospinal fluid contacting neuron in dorsal raphe nucleus with up-regulated expression.Conclusion: Morphine-dependent and withdrawal can activate the distal cerebrospinal fluid contacting neurons phosphorylation CREB in rat brain. The cerebrospinal fluid contacting neuron is related to morphine withdrawal and dependence rats.