Circadian variations of Prostaglandin E2 and F2á release in the Golden Hamster retina

DE ZABALIA, N; GOLOMBEK, DA; SILBERMAN, M; ROSENSTEIN, RE

JOURNAL OF NEUROCHEMISTRY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2010 vol. 112 p. 972 - 979

0022-3042

Circadian variations of prostaglandin E2 and F2a release were examined in the golden hamster retina. Both parameters showed significant diurnal variations with maximal values at midnight. When hamsters were placed under constant darkness for 48 h, the differences in prostaglandin release between subjective midday and subjective midnight persisted. Western blot analysis showed that cyclooxygenase-1 levels were significantly higher at midnight than at midday, and at subjective midnight than at subjective midday, whereas no changes in cyclooxygenase-2 levels were observed among these time points. Immunohistochemical studies indicated the presence of cyclooxygenase-1 and cyclooxygenase-2 in the inner (but not outer) retina. Circadian variations of retinal prostaglandin release were also assessed in suprachiasmatic nuclei (SCN)-lesioned animals. Significant differences in retinal prostaglandin release between subjective midday and subjective midnight were observed in SCN-lesioned animals. These results indicate that hamster retinal prostaglandin release is regulated by a retinal circadian clock independent from the SCN. Thus, the present results suggest that the prostaglandin/cyclooxygenase -1 system could be a retinal clock output or part of the retinal clock mechanism.