Elevated glucocorticoid levels are responsible for induction of tyrosine hydroxylase mRNA expression, phosphorylation, and enzyme activity in the nucleus of the solitary tract during morphine withdrawal.

ABSTRACT: Chronic opiate exposure induces neurochemical adaptations in the noradrenergic system. Enhanced responsiveness of the hypothalamo-pituitary-adrenal axis after morphine withdrawal has been associated with hyperactivity of ascending noradrenergic input from the nucleus of the solitary tract (NTS-A(2)) cell group to the hypothalamic paraventricular nucleus (PVN). This study addressed the role of morphine withdrawal-induced corticosterone (CORT) release in regulation of tyrosine hydroxylase (TH), the rate-limiting enzyme of catecholamine biosynthesis in adrenalectomized (ADX) rats supplemented with low CORT pellet (ADX plus CORT). Present results show that in sham-ADX rats, noradrenergic neurons in the NTS-A(2) became activated during morphine withdrawal, as indicated by increased TH mRNA expr

SUBMITTER: Nunez C 

PROVIDER: S-EPMC2703550 | biostudies-literature | 2009 Jul

REPOSITORIES: biostudies-literature