Day/night changes of pineal gland volume and pinealocyte nuclear size assessed over 10 consecutive days

Abstract

Previous studies aimed at elucidating day/night changes of pineal gland size and pinealocyte nuclear volume have yielded contradictory results. The aim of the present investigation was to examine the above parameters over a period of 10 successive days, at 6-hour intervals under a lighting regimen of LD 12:12 (7 a.m. to 7 p.m.). It was found that changes in pineal gland volume could not be correlated with the light/dark phases; instead, a rhythm with a two-day period was encountered. Pinealocyte nuclear volume, by contrast, showed clear circadian changes, exhibiting troughs during photophase and peaks during scotophase. In this experimental series, the karyometric results conformed to the melatonin forming rhythm in the rat pineal gland as reported in the literature.

Ultrastructure of the mammalian pinealocyte under natural and experimental conditions: Quantitative aspects

“…In recent electron-microscopic studies of the rat pinealocytes we found larger nuclear cross-sectional areas at night as compared to those during daytime (Karasek et al, 1990). The latter results are in agreement with day/ night changes observed in the rat pinealocytes nuclear size by Diehl et al (1984) during 10 consecutive days, and also in the golden hamster by Dombrowski and McNulty (19841, but contrary to those observed in the Chinese hamster (Matsushima et al, 1989). A reason for the discrepancy in the karyometric data remains unexplained.…”

“…A reason for the discrepancy in the karyometric data remains unexplained. Diehl et al (1984) concluded that there did not appear to be a consistent correlation between the size of pinealocyte nuclei and the level of pinealocyte activity related to melatonin production. Therefore, karyometry seems to be a questionable technique for monitoring circadian changes in pinealocytes.…”

Pineal-Thyroid Cytophysiological Responsiveness to Altered Steroid Hormone and Antihormone Milieu in Rat (Rattus rattus)

“…It is interesting to note that the cytophysiological changes indicated by karyomorphological alterations in the pineal gland (Quay, 1965(Quay, , 1976Diehl et al, 1984;Sahu & Chakraborty, 1983, 1986Hira et al, 1989;Peschke et al, 1989;Martinez Soriano et al, 1990) and thyroid (Chakraborty et al, 1992;Ganguli et al, 1998) in mammals provide inextricable indices of the nature of activities of these glands.…”

“…Extensive studies have shown that in pineal and thyroid, an active phase, is characterized by increased nuclear size indicating stimulation of pineal and thyroid synthesis activity whereas inhibition of the pineal and thyroid is characterized by decreased nuclear size (Quay, 1965(Quay, , 1976Chakraborty & Maiti, 1981;Chakraborty & Maitra, 1982;Maiti & Chakraborty, 1982;Diehl et al, 1984;Sahu & Chakraborty, 1983, 1986Chaudhuri & Maiti, 1989;Hira et al, 1989;Peschke et al, 1989;Martinez Soriano et al, 1990;Chakraborty et al, , 1992Chakraborty, 1981Chakraborty, , 1993Chakraborty, , 1994Chakraborty & Sarkar, 1994;Ganguli et al, 1998Ganguli et al, , 2001Bandopadhyay et al, 2000).…”

Metyrapone, a corticoid inhibitor, induces inverse changes in pineal and adrenal karyomorphology, dynamics and function in mice (Mus musculus)

“…In all cases pineal (Quay, 1976;Chakraborty, , 1993Chakraborty, , 1994Chakraborty and Maiti, 1981;Chakraborty et al, , 1982Chakraborty et al, , 1994Diehl et al, 1984;Hira et al, 1989;Bandopadhyay and Chakraborty, 2010;Sinha et al, 2009) and adrenal (Miller, 1954;Maitra and Chakraborty, 1983;Chakraborty, 1994; cytological studies were made from midsagittal paraffin sections of 5 µm thickness stained following haematoxylin-eosin and observed under oil immersion (15 ocular x 100 objective). Only the right adrenal glands were used for histological studies.…”