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Inhibitory effect of neuropeptide Y on morphine withdrawal is accompanied by reduced c‐ fos expression in specific brain regions
Author(s) -
Clausen T.R.,
Møller M.,
Woldbye D.P.D.
Publication year - 2001
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.1092
Subject(s) - locus coeruleus , neuropeptide y receptor , morphine , (+) naloxone , endocrinology , medicine , periaqueductal gray , brainstem , neuropeptide , opioid , stimulation , inhibitory postsynaptic potential , chemistry , central nervous system , receptor , midbrain
Neuropeptide Y (NPY) was previously shown in our laboratory to attenuate behavioral signs of morphine withdrawal. To further characterize the anti‐withdrawal effect of NPY, the present study attempted to identify specific brain regions where NPY inhibits neuronal activity during withdrawal. Morphine dependence was induced in male Wistar rats by two daily subcutaneous injections of morphine at increasing doses, and the withdrawal syndrome was precipitated acutely by intraperitoneal administration of naloxone. Rats were pre‐treated with an intracerebroventricular (icv) injection of NPY (12 nmol) or vehicle 30 min before the naloxone challenge. Withdrawal behavior was quantified using a point scoring technique based on motor‐ and non‐motor‐related signs. Brain areas involved in the attenuation of morphine withdrawal were delineated by radioactive in situ hybridization for the immediate early gene c‐ fos , which is a marker for neuronal activity. The present study confirmed the inhibitory effect of NPY on withdrawal behavior. Inhibition of behavioral signs of naloxone‐precipitated morphine withdrawal was accompanied by significantly reduced c‐ fos expression in the locus coeruleus, lateral septal nucleus, ventral part of the periaqueductal grey, cingulate and frontal cortices, and septohippocampal nucleus. Our data suggest that neo‐ and allo‐cortical areas as well as specific brainstem nuclei are involved in the anti‐withdrawal effects of NPY. J. Neurosci. Res. 64:410–417, 2001. © 2001 Wiley‐Liss, Inc.