title: The inability of chronic mianserin to block central alpha 2-adrenoceptors.
abstract: An investigation was undertaken of the effect of long-term mianserin administration on the clonidine-induced decrease in rat brain MHPG-SO4 content. The dose of clonidine (0.1 mg/kg) chosen was one considered to selectively activate central alpha 2-adrenoceptors. Mianserin (10 mg/kg) given once daily for 9 and 15 days failed to alter the response to clonidine. This contrasts with the observations that acute and 5 day mianserin treatment blocks the clonidine-induced reduction in rat brain MHPG-SO4 levels. The possibility of mianersin-induced changes in the sensitivity of alpha 2-adrenoceptors is discussed. Chronic mianserin administration was associated with elevated levels of MHPG-SO4. This may have resulted from blockade of alpha 1-adrenoceptors.
mesh_terms: D000317:Adrenergic alpha-Antagonists; D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D003000:Clonidine / Q000494:pharmacology; D003984:Dibenzazepines / Q000494:pharmacology*; D008297:Male; D008734:Methoxyhydroxyphenylglycol / Q000378:metabolism; D008803:Mianserin / Q000494:pharmacology*; D051381:Rats; D013997:Time Factors
chemical_list: D000317:Adrenergic alpha-Antagonists; D003984:Dibenzazepines; D008803:Mianserin; D008734:Methoxyhydroxyphenylglycol; D003000:Clonidine