Influence of propranolol, phenoxybenzamine or phentolamine on the in vivo nocturnal rise of pineal melatonin levels in the syrian hamster

J. Stuart Lipton, Larry J. Petterborg, Russel J. Reiter

Research output: Contribution to journalArticlepeer-review

42 Scopus citations

Abstract

In the Syrian hamster, pineal melatonin levels exhibit a 15-fold rise during the dark phase of the light: dark cycle. This rise is believed to be mediated by the release of norepinephrine from the postganglionic sympathetic fibers which terminate within the pineal. In order to determine the nature of the adrenergic receptor involved in the norepinephrine mediated nocturnal increase in melatonin, male hamsters were treated with either α- or β-adrenergic blockers just prior to lights out. Subsequently, radioimmunoassayable levels of melatonin were measured at 7, 8 and 9 hours (0300, 0400 and 0500 h, respectively) into the dark period. Propranolol (20 mg/kg) completely suppressed the nocturnal rise of melatonin while phentolamine (10 mg/kg) had no effect upon the increase. The minimum amount of propranolol necessary to block the nighttime rise of melatonin was determined to lie between 1 mg/kg and 10 mg/kg. Phenoxybenzamine (20 mg/kg) exhibited a slight, although statistically significant, blockade of the nocturnal melatonin rise.

Original languageEnglish (US)
Pages (from-to)2377-2382
Number of pages6
JournalLife Sciences
Volume28
Issue number21
DOIs
StatePublished - May 21 1981

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)

Fingerprint Dive into the research topics of 'Influence of propranolol, phenoxybenzamine or phentolamine on the in vivo nocturnal rise of pineal melatonin levels in the syrian hamster'. Together they form a unique fingerprint.

Cite this