C. Ribelayga et al., ADRENERGIC AND PEPTIDERGIC REGULATIONS OF HYDROXYINDOLE-O-METHYLTRANSFERASE ACTIVITY IN RAT PINEAL-GLAND, Brain research, 777(1-2), 1997, pp. 247-250
Mechanisms involved in the regulation of hydroxyindole-O-methyltransfe
rase (HIOMT) activity were investigated in the rat pineal. Isoproteren
ol, db-cAMP, PACAP or VIP had no acute (6 h) effect whereas NPY, thaps
igargin and a PKC activator stimulated HIOMT activity by 30-40%. Chron
ic stimulation (6 days) with isoproterenol, db-cAMP, or each peptide p
revented the long-term decrease of HIOMT activity. Phenylephrine had n
either short- nor long-term effect on enzyme activity. These results i
ndicate that HIOMT activity is long- and short-term regulated by vario
us neurotransmitters. (C) 1997 Elsevier Science B.V.