The association between melatonin production and electrophy siology of the guinea pig pineal gland
Article first published online: 30 JAN 2007
Journal of Pineal Research
Volume 21, Issue 2, pages 80–90, September 1996
How to Cite
McCance, I., Partington, H.C. and Coleman, H.A. (1996), The association between melatonin production and electrophy siology of the guinea pig pineal gland. Journal of Pineal Research, 21: 80–90. doi: 10.1111/j.1600-079X.1996.tb00274.x
- Issue published online: 30 JAN 2007
- Article first published online: 30 JAN 2007
- Received March 5,1996;; accepted May 10,1996.
- action potential-like spikes;
- β-adrenoceptor agonist;
- calcium entry;
- melatonin production
Abstract: Melatonin production by isolated pineal glands from guinea pigs was examined under conditions that affect membrane potential or the firing of action potential-like spikes. In glands from superior cervical ganglionectomized animals, depolarization resulting from increasing extracellular potassium concentration to 100 mM did not initiate melatonin production, and it delayed the response to the β-adrenoceptor agonist orciprenaline. In glands from intact animals, melatonin production was initiated by exposure to 100 mM potassium with a time-course similar to the response to orciprenaline. A proportion of this response was propanol resistant, suggesting that the normal control of melatonin production may involve a neurotransmitter in addition to norepinephrine. Exposure to verapamil or nifedipine, or removal of extracellular calcium, previously shown to eliminate action potential-like spikes, did not substantially affect the increase in melatonin production induced by orciprenaline. Phenylephrine, which stimulates spiking, produced only a slight increase in melatonin production. It is concluded that the depolarization and the spiking are not closely related to the stimulation of melatonin production, but may relate principally to the secretion of a substance other than melatonin.