Circadian rhythms and environmental lighting regulate a number of endocrine and behavioral functions. Dispersed chick pineal cells remain rhythmic and responsive to light in culture. Light has two effects on the melatonin rhythm: acute suppression and entertainment (phase shifts) of the underlying clock. The key enzyme in melatonin synthesis, serotonin N-acetyltransferase was partially purified, separated and distinguished from a related, drug-metabolizing, enzyme. Caffeine, at concentrations that release calcium from intracellular stores, induced light-like phase shifts in the melatonin rhythm while increasing melatonin synthesis. Thapsigargin and EGTA each blocked the entraining effects of caffeine and of light. These results point toward a role for intracellular calcium fluxes in entertainment of the circadian pacemaker.
| Yadav, Geetha; Straume, Martin; Heath 3rd, James et al. (2003) Are changes in MAPK/ERK necessary or sufficient for entrainment in chick pineal cells? J Neurosci 23:10021-31 |
| Zatz, Martin (2003) Stands to reason. J Biol Rhythms 18:3 |
| Natesan, Arjun; Geetha, L; Zatz, Martin (2002) Rhythm and soul in the avian pineal. Cell Tissue Res 309:35-45 |
| Zatz, Martin (2002) Can't get no ... satisfaction! J Biol Rhythms 17:391 |
| Zatz, Martin (2002) Who do you think you are? J Biol Rhythms 17:283 |
| Zatz, Martin (2002) Ya gotta believe! J Biol Rhythms 17:3 |
| Zatz, M; Gastel, J A; Heath 3rd, J R et al. (2000) Chick pineal melatonin synthesis: light and cyclic AMP control abundance of serotonin N-acetyltransferase protein. J Neurochem 74:2315-21 |
| Bernard, M; Guerlotte, J; Greve, P et al. (1999) Melatonin synthesis pathway: circadian regulation of the genes encoding the key enzymes in the chicken pineal gland and retina. Reprod Nutr Dev 39:325-34 |
