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Indian Journal of Experimental Biology (IJEB) >
IJEB Vol.44 [2006] >
IJEB Vol.44(01) [January 2006] >
| Title: | Air-breathing rhythm in Clarias batrachus (Linn.): Modulatory role of eyes, pineal and exogenous melatonin |
| Authors: | Sahu, Swati
Shedpure, Maya |
| Keywords: | Air-breathing
Blinding
Catfish
Circadian rhythm
Enucleation
Pineal |
| Issue Date: | Jan-2006 |
| Publisher: | CSIR |
| Abstract: | Effects
of enucleation followed by pinealectomy and administration of exogenous
melatonin on air-breathing activity rhythm in a fresh water catfish, C. batrachus maintained at LD 12:12 and
laboratary temperature during its prepratory phase, were examined. Results of
cosinor analysis clearly reveal that most of the intact individuals exhibited
circadian rhythm in their air-breathing activity and such rhythm persists even
after enucleation followed by pinealectomy and then melatonin administration.
However, the period ( ) of the activity obtained by power spectrum
analysis was prominent 24 hr in most of the intact individuals, but it was
increased ( > 24 hr) after enucleation in most of the
individuals. In most of the enucleated + pinealectomized individuals was less than 24 hr, and after receiving
melatonin treatment was shifted to prominent
24 hr in most of the individuals. In addition, visual analysis of the actograms
depicted that in intact individuals air-breathing activity is entrained with
the timings of lights on/off with elevation of activity during dark period and
decreased activity during light hours. However, enucleated and enucleated +
pinealectomized individuals showed free run in their activity rhythm. The
treatment of melatonin reestablished the entrainment of activity atleast with
the timing of lights off, in most of the studied individuals. Further, daily
mean of the air-breathing activity was decreased in enucleated +
pinealectomized individuals as compared with other studied groups (intact,
enucleated, enucleated + pinealectomized + melatonin receiving). It could be
speculated that there may be existence of extraretinal and extrapineal
photoreceptors in C. batrachus.
However, eyes play an important role in regulating air-breathing activity
rhythm in such species. In addition, exogenous melatonin may also have some
modulatory effect on such rhythm. |
| Page(s): | 55-62 |
| ISSN: | 0975-1009 (Online); 0019-5189 (Print) |
| Source: | IJEB Vol.44(01) [January 2006]
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