IMPORTANCE OF LIGHT IN TEMPORAL ORGANIZATION OF PHOTORECEPTOR PROTEINS AND MELATONIN-PRODUCING SYSTEM IN THE PINEAL OF CARPCATLA CATLA

Jun 8, 2010Chronobiology international

Light’s role in timing the proteins for light sensing and melatonin production in the pineal gland of carp Catla catla

AI simplified

Circadian Biology on OpenScience ↗PubMed ↗DOI ↗

Abstract

Daily rhythmicity of pineal proteins and melatonin levels peaked at 12:00 h in fish under natural light conditions.

Pineal rod-like opsin and alpha-transducin showed a peak band intensity at 12:00 h and a low intensity at 24:00 h in fish exposed to natural photoperiod.
In continuous illumination, band intensities of these proteins remained high, while under darkness, they were low at all times measured.
Pineal AANAT, serum melatonin, and calcium levels were highest at 24:00 h and lowest at 12:00 h in fish under natural light.
Both serum and intra-pineal calcium levels were significantly lower in continuous illumination and higher in darkness at each measurement point.
The absence of daily rhythm in these variables under continuous light and darkness indicates dependence on external light conditions for circadian organization.

AI simplified

The importance of light in the temporal organization of photoreceptor proteins and melatonin-producing system has been investigated for the first time in the pineal of a tropical fish. In this study, an identical experimental paradigm was followed during the four distinct phases of an annual cycle in adult carps (Catla catla) maintained either under natural photoperiod (NP) or continuous illumination (LL) or darkness (DD) for 30 days. At the end of each experiment, the pineal from fish in each experimental group was collected either at 06:00, 12:00, 18:00, or 24:00 in a daily cycle and assessed by Western blot analysis for pineal rod-like opsin, alpha-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 alpha-transducin in NP fish, while the band intensities of these photo-pigment 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.

Full Text

Full text is available at the source.

View full text ↗

IMPORTANCE OF LIGHT IN TEMPORAL ORGANIZATION OF PHOTORECEPTOR PROTEINS AND MELATONIN-PRODUCING SYSTEM IN THE PINEAL OF CARPCATLA CATLA

Abstract

Full Text

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief

Abstract

Full Text

Related papers

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief