Prazosin increases immobility episodes in taiep rats without changes in the properties of alpha1 receptors.
The taiep rat is a myelin mutant in which immobility episodes (IEs) can be induced in adult males by gripping. EEG recordings during gripping-induced IEs show a rapid eye movement (REM) sleep-like pattern, similar to that reported for narcolepsy-cataplexy suggesting that IEs represent a disorder of REM-sleep. An alpha(2) adrenoceptor agonist increases gripping-induced IEs, whereas alpha(2) antagonists decrease these. We have studied the effect of prazosin on IEs and the levels of alpha(1) adrenoceptors were evaluated in cerebro-cortical homogenates of taiep and control rats. Systemic administration of prazosin results in a significant increase in both the frequency and duration of gripping-induced IEs. Our results show that cerebro-cortical tissue is not an adequate candidate for the expression of cataplexy-like symptoms, but prazosin, an alpha(1) antagonist, is a potent inducer of gripping-induced immobility episodes in taiep rats.
Cortés
Ma-del-Carmen
MD
Instituto de Fisiología and Secretaría General, Benemérita Universidad Autónoma de Puebla, Apdo. Postal 5-66, C.P. 72430 Puebla, Pue., México.
Arias-Montaño
José A
JA
Eguibar
José-R
JR
D058668:Adrenergic alpha-1 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists / Q000493:pharmacokinetics / Q000494:pharmacology; D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D001921:Brain / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D001923:Brain Chemistry / Q000187:drug effects; D002385:Cataplexy / Q000209:etiology / Q000503:physiopathology*; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography / Q000187:drug effects; D020279:Hereditary Central Nervous System Demyelinating Diseases / Q000150:complications / Q000503:physiopathology*; D008297:Male; D011224:Prazosin / Q000493:pharmacokinetics / Q000494:pharmacology*; D051381:Rats; D011922:Rats, Mutant Strains; D011930:Reaction Time / Q000187:drug effects; D018340:Receptors, Adrenergic, alpha-1 / Q000378:metabolism*
D058668:Adrenergic alpha-1 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists; D018340:Receptors, Adrenergic, alpha-1; D011224:Prazosin