Regulation of the adrenomedullary catecholaminergic system after mild, acute stress.
The time course of regulation of rat adrenomedullary phenylethanolamine N-methyltransferase (PNMT) and tyrosine hydroxylase (TH) activity was studied after a single episode of 20-min restraint stress. Significant increases in PNMT and TH activity were observed 18 h after the beginning of the stress. The time course of acute stress-induced regulation of PNMT and TH was examined for the influence of neural and hormonal input. Unilateral denervation was performed, and the animals were exposed to a single episode of restraint. PNMT activity increased similarly in both the innervated and denervated adrenals, with a significant increase observed at 36 h after the stress. TH activity was similar in both denervated and innervated adrenals, with a significant increase observed at 24 and 36 h after stress. Finally, suppression of endogenous corticosterone with dexamethasone delayed the stress-induced increase in activity of PNMT but not TH. The present study indicates that increases in catecholamine biosynthetic enzymes can be observed after a single episode of mild, acute stress. In addition, glucocorticoids appear to be important in the time course of the stress-induced increase in PNMT but not TH activity, whereas neural input does not seem to affect the time course of these increases.
Betito
K
K
Department of Pharmacology and Therapeutics, Douglas Hospital Research Center, McGill University, Montreal, Quebec, Canada.
Mitchell
J B
JB
Bhatnagar
S
S
Boksa
P
P
Meaney
M J
MJ
D000208:Acute Disease; D000311:Adrenal Glands / Q000294:innervation; D000313:Adrenal Medulla / Q000378:metabolism*; D000818:Animals; D002395:Catecholamines / Q000378:metabolism*; D003345:Corticosterone / Q000037:antagonists & inhibitors; D003714:Denervation; D003907:Dexamethasone / Q000494:pharmacology; D008297:Male; D010625:Phenylethanolamine N-Methyltransferase / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012149:Restraint, Physical; D013312:Stress, Physiological / Q000209:etiology / Q000378:metabolism*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
D002395:Catecholamines; D003907:Dexamethasone; D014446:Tyrosine 3-Monooxygenase; D010625:Phenylethanolamine N-Methyltransferase; D003345:Corticosterone