Swimming-Induced Suppression of Rat Pineal Melatonin is Prevented by Pretreatment with Calcium Channel Blockers

Dougal J. Morton, Russel J. Reiter, Gerald R. Buzzell

Research output: Contribution to journalArticle

9 Scopus citations


Young adult male rats were treated with isoproterenol during the day to induce high levels of pineal N-acetyltransferase (NAT) activity and melatonin. Roughly 2 hr later when pineal NAT activity and melatonin levels were elevated, animals were given either an injection of a calcium channel blocker, i.e., either nifedipine or verapamil, or diluent. The rats were then forced to swim for 10 min in room temperature (22°C) water. Fifteen minutes after swimming onset, pineal glands were collected for measurement of NAT activity and melatonin. Swimming caused a dramatic reduction in pineal melatonin content without influencing NAT activity. Nifedipine substantially and verapamil completely blocked the drop in pineal melatonin levels due to swimming without influencing NAT activity. The results suggest that calcium may be somehow directly or indirectly involved in melatonin release from the rat pineal gland.

Original languageEnglish (US)
Pages (from-to)105-108
Number of pages4
JournalProceedings of the Society for Experimental Biology and Medicine
Issue number1
StatePublished - Jan 1989


ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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