Clonidine diminishes c-jun gene expression in the cardiovascular sensitive areas of the rat brainstem.
The present study investigated the effect of clonidine on the basal and inducible c-jun and c-fos mRNA expression in the nucleus tractus solitarius (middle, mNTS, and rostral, rNTS) and the rostral ventrolateral medulla (caudal, cRVLM, and rostral, rRVLM). Conscious rats received saline, clonidine (30 microg/kg, i.v.), saline plus sodium nitroprusside (NP), or clonidine plus NP. Under basal conditions (saline-infused rats), c-jun mRNA was expressed in the mNTS and rRVLM but not in the rNTS or cRVLM whereas c-fos mRNA was not detectable. Clonidine attenuated the increases in c-fos in the mNTS and cRVLM and c-jun gene expression in the mNTS and rRVLM caused by NP-evoked hypotension and also reduced the basal expression of c-jun mRNA in the mNTS and rRVLM. These findings establish a causal link between clonidine inhibition of c-fos expression in brainstem and its hypotensive action, and provide the first evidence that clonidine attenuates the expression of the closely linked c-jun gene in neurons implicated in centrally mediated hypotension.
El-Mas
M M
MM
Department of Pharmacology, School of Medicine, East Carolina University, Greenville, NC, USA.
Abdel-Rahman
A A
AA
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D001933:Brain Stem / Q000187:drug effects* / Q000502:physiology; D003000:Clonidine / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects*; D016762:Genes, fos / Q000187:drug effects; D016758:Genes, jun / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects*; D008297:Male; D016755:Proto-Oncogene Proteins c-jun / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley
D016755:Proto-Oncogene Proteins c-jun; D012333:RNA, Messenger; D003000:Clonidine