Neuropeptide Y-mediated pressor responses following high-frequency stimulation of the rat sympathetic nervous system.

Neuropeptide Y (NPY) is a potent pressor agent that is stored in the sympathetic nerves. In several species, NPY release is augmented when sympathetic impulse frequencies increase. We investigated the extent to which NPY contributes to the pressor response to high- and low-frequency electrical stimulation.

Nonadrenal epinephrine-forming enzymes in humans. Characteristics, distribution, regulation, and relationship to epinephrine levels.

Animal studies indicate that nonadrenal tissues may synthesize epinephrine (E). Here we demonstrate phenylethanolamine N-methyltransferase (PNMT) and/or nonspecific N-methyltransferase (NMT) enzymatic activity in human lung, kidney, heart, liver, spleen, and pancreas. There was a significant overall correlation (r = 0.

Glucocorticoid elevation of mRNA encoding epinephrine-forming enzyme in lung.

The epinephrine-forming enzyme phenylethanolamine N-methyltransferase (PNMT) is present in lung and its activity is increased by the glucocorticoid dexamethasone. Chronic administration of dexamethasone (0.5 mg/kg twice daily) doubled levels of mRNA coding for PNMT in rat lung.

Propranolol reduces rat dopamine-beta-hydroxylase activity and catecholamine levels.

Propranolol treatment (1 mg/kg i.p. twice daily for 8 days) reduced atrial dopamine-beta-hydroxylase (D beta H) activity by 60.