Influence of sino-aortic baroreceptor denervation on catecholamines, catecholamine-synthesizing enzymes and choline acetyltransferase activity in the brainstem nuclei of the rat.
At one week after sino-aortic baroreceptor denervation in the rat, aortic blood pressure and plasma contents of epinephrine and dopamine beta-hydroxylase (DBH) activity were elevated during resting and conscious states. Stress-induced elevation of blood pressure and plasma epinephrine were markedly pronounced. These changes disappeared at four weeks after denervation. Sino-aortic deafferentation decreased choline acetyltransferase (ChAc) activity in the nucleus tractus solitarii (NTS) and locus coeruleus (LC) and increased DBH activity, norepinephrine levels, phenylethanolamine N-methyltransferase (PNMT) activity and epinephrine levels in the LC, accompanied with a reduction of DBH activity and norepinephrine contents in the nucleus hypothalamicus posterior. These alterations were confirmed one week after denervation but did not persist for a period of four weeks. At four weeks after denervation, ChAc activity was significantly decreased in the nucleus dorsalis nerve of the vagi but not in ;the nucleus ambiguus. During the transient hypertensive phase, sino-aortic deafferentation did not alter DBH and PNMT activities in the NTS, A2 cell and A1 cell areas, and both catecholamine levels in the NTS. In conclusion, sino-aortic denervation transiently decreased ChAc activity in the NTS and LC, and enhanced synthesis and accumulation of norepinephrine and epinephrine in the LC accompanied with a decrease in norepinephrine contents and DBH activity in the nucleus hypothalamicus posterior, causally resulting in short-lasting labile hypertension and activation of the adrenal medulla.
D000818:Animals; D001011:Aorta / Q000294:innervation*; D001794:Blood Pressure; D001933:Brain Stem / Q000032:analysis*; D002395:Catecholamines / Q000032:analysis* / Q000097:blood; D002795:Choline O-Acetyltransferase / Q000032:analysis*; D003714:Denervation; D004299:Dopamine beta-Hydroxylase / Q000032:analysis*; D008297:Male; D010625:Phenylethanolamine N-Methyltransferase / Q000032:analysis*; D011311:Pressoreceptors / Q000502:physiology*; D051381:Rats; D013312:Stress, Physiological / Q000503:physiopathology
D002395:Catecholamines; D004299:Dopamine beta-Hydroxylase; D010625:Phenylethanolamine N-Methyltransferase; D002795:Choline O-Acetyltransferase