Effects of chronic atropine administration on regional vasoactive intestinal polypeptide concentrations in rat brain.
We studied the effects of 14 days' treatment with atropine sulfate (10 or 20 mg/kg per day) or atropine methyl bromide (20 mg/kg per day) on the concentration of vasoactive intestinal polypeptide like-immunoreactivity (VIP-LI) in the rat brain. VIP-LI in the anterior pituitary as well as brain areas dissected from treated and control rats was measured by radioimmunoassay. VIP-LI in the hypothalamus, and especially in the suprachiasmatic nucleus, was not affected by chronic atropine sulfate administration. Conversely, the same treatment induced a decrease in VIP-LI in the cerebral cortex, dorsal raphe, locus coeruleus, ventrolateral and dorsolateral medulla. In these structures, the decrease in VIP-LI was probably due to muscarinic receptor blockade in the central nervous system rather than in the peripheral nervous system since variations in VIP-LI were not observed after atropine methyl bromide treatment. These findings suggest the existence of a muscarinic control of VIP-LI in discrete brain areas of the rat and particularly in caudal brainstem structures.
Petit
J M
JM
Laboratoire de Médecine Expérimentale, INSERM U52-CNRS URA 1195, Université Claude Bernard, Lyon, France.
Denoroy
L
L
Jouvet
M
M
D000818:Animals; D001285:Atropine / Q000494:pharmacology*; D001286:Atropine Derivatives / Q000494:pharmacology; D001921:Brain / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D008297:Male; D018727:Muscarinic Antagonists; D011863:Radioimmunoassay; D051381:Rats; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism*
D001286:Atropine Derivatives; D018727:Muscarinic Antagonists; D014660:Vasoactive Intestinal Peptide; D001285:Atropine; C006649:methylatropine