IMPORTANCE OF LIGHT IN TEMPORAL ORGANIZATION OF PHOTORECEPTOR PROTEINS AND MELATONIN-PRODUCING SYSTEM IN THE PINEAL OF CARP CATLA CATLA (original) (raw)

Western blot analysis for pineal rod-like opsin, α-transducin, and AANAT. The same animals were also used for measurement of serum melatonin levels, and the serum as well as intra-pineal Ca ++ levels at each timepoint. The study revealed a daily rhythmicity with a peak at 12:00 h and nadir at 24:00 h in the band intensity of pineal rod-like opsin and α-transducin in NP fish, while the band intensities of these photopigment proteins remained high under LL and low under DD, irrespective of clock hour during the 24 h cycle. The band intensity of pineal AANAT, levels of serum melatonin, and both serum Ca ++ and intra-pineal Ca ++ were maximum at 24:00 h and minimum at 12:00h in NP fish, and they were significantly lower under LL and higher under DD at each point of study. The results showed loss of daily rhythm in each studied variable in both LL and DD carps, suggesting that their circadian organization is dependent on the external light-dark conditions, rather than an endogenous circadian oscillator in the pineal.