Quantitative Cytological Analysis of Functional Changes in Adrenomedullary Chromaffin Cells in Normal, Sham‐Operated, and Pinealectomized Rats in Relation to Time‐of‐day: II. Nuclear‐Cytoplasmic Ratio, Nuclear Size, and Pars Granulosa of Nucleolus

Abstract

Adrenaline(A)- and noradrenaline(N)-cells in the adrenal medulla of nonoperated (NO), sham-operated (SO), and pinealectomized (PX) male rats (n = 125) were investigated by quantitative electron and light microscopy. Animals were killed at eight time points during a standardized 24-h, light-dark (12:12) cycle 14 days after surgery. Nuclear-cytoplasmic (N/P) ratios, diameters of nuclei, and the frequency of nucleoli showing a large amount of pars granulosa (granulated nucleoli), were the primary characteristics studied. Major findings include the following: 1) The frequency of low N/P ratios over a 24-h period tended to be higher in PX animals than in controls in A-cells, as shown in large cell profiles (P less than 0.02); but such a tendency was not apparent in N-cells. Daily mean nuclear diameters were similar among the three experimental groups. 2) The 24-h changing pattern of phase relations in the frequency of low N/P ratio and nuclear size differed between A- and N-cells in NO and SO but not in PX animals. 3) The frequency of granulated nucleoli in A-cells was much higher in PX animals than in NO and SO animals throughout a 24-h period (P less than 0.018), especially from the late light to early dark phase (P less than 0.003), and higher in A-cells than in N-cells generally (P less than 0.0009). Pinealectomy thus caused increases in the cytoplasm and in the pars granulosa of the nucleolus in many A-cells; changes in N-cells were less apparent. This suggest a disturbed balance and coordination between A- and N-cell systems of adrenal medulla following pinealectomy.

Quantitative Cytological Analysis of Functional Changes in Adrenomedullary Chromaffin Cells in Normal, Sham‐Operated, and Pinealectomized Rats in Relation to Time of Day: III. Nuclear Density

“…Related results have been reported also in circadian rhythms of activity [Redman et al, 1983;Armstrong et al, 19861, oxygen consumption and evaporative water loss [Harlow, 19871, and plasma prolactin level and hair follicle growth [Allain et al, 1986;Mori and Okamura, 19861. Moreover, the temporal relationship of 24 hr changes in the cell size tended to be different between A and N cells in the NO and the SPX groups but not in the PX group. Related results were reported in our previous electron microscopic study on the frequency of cell profiles showing low nuclearkytoplasmic ratios [Kachi et al, 1988a]. These results support the hypothesis of the pineal action being phase-tuning and coordinating of at least several circadian systems in the body [Kachi et al, 1979[Kachi et al, , 1980a[Kachi et al, , 1985bKachi, 19871. The effect of pinealectomy and the time at which the effect of pinealectomy became evident were different depending on the morphological parameters examined [Kachi et al, 1979[Kachi et al, , 1980a[Kachi et al, ,b, 1984[Kachi et al, , 1985a[Kachi et al, , 1988a study; see also Halberg and Barnum, 1961, and Halberg et al, 19861.…”

“…Related results were reported in our previous electron microscopic study on the frequency of cell profiles showing low nuclearkytoplasmic ratios [Kachi et al, 1988a]. These results support the hypothesis of the pineal action being phase-tuning and coordinating of at least several circadian systems in the body [Kachi et al, 1979[Kachi et al, , 1980a[Kachi et al, , 1985bKachi, 19871. The effect of pinealectomy and the time at which the effect of pinealectomy became evident were different depending on the morphological parameters examined [Kachi et al, 1979[Kachi et al, , 1980a[Kachi et al, ,b, 1984[Kachi et al, , 1985a[Kachi et al, , 1988a study; see also Halberg and Barnum, 1961, and Halberg et al, 19861. Thus complex mechanisms involving the center of sympathoadrenomedullary system and the adrenal cortex seem to be involved in the pineal-adrenomedullary relation.…”

Influence of the pineal and melatonin administration on the day‐night changes in the adrenal catecholamines of young chicks

“…Similar to this finding, effects of shampinealectomy long after surgery have been reported by several authors (Meyer and Quay, 1976;Gorray and Quay, 1978;Banerji et al, 1980;Kachi et al, 1979Kachi et al, , 1980Banerji and Quay, 1986). Although the underlying mechanism for the effects of sham-pinealectomy on adrenal catecholamines remain to be elucidated, it might be that the surgical stress or trauma has repercussions on the adrenomedullary nerve endings (Kachi et al, 1988). However, the present study on shamoperated chicks showing marked changes in E but not in NE, in contrast to the morphological changes in both E and NE in the adrenal of similarly treated rats , underlines that the neural regulation of NE synthesis in the adrenal may be different in chicks and rats (see Mahata and Ghosh, 1985).…”

Effects of Pinealectomy on the Mitotic Activity of Adrenomedullary Chromaffin Cells in Relation to Time of Day

“…We have reported data suggesting increased activity in the daily dark phase and increased amplitude of the 24-h change in the activity of the preganglionic nerve endings on the adrenomedullary A cells [Kachi et al, 1979;1980bl. In contrast, neither N cells nor the nerve endings on them in pinealectomized animals generally showed increased levels or amplitudes in 24-h rhythms of functional and quantitative morphological parameters, except for the 24-h changes in the number of large granular vesicles in the nerve endings [Kachi et al, 1980a[Kachi et al, , 1984[Kachi et al, , 1988a. The above-mentioned differential influence on preganglionic neurons by central monoaminergic neurons [Lau et al, 19871 may interpret these results at least partially; that is, pinealectomy causes a reduction of the activity of serotonergic neurons, which results in suppression of the N cell system and activation of supraspinal noradrenergic fibers having the facilitatory influence on the development of adrenomedullary A cells via preganglionic neurons, at least in a certain phase during the 24-h period [see also, Kachi, 19871. The second possibility is the influence by humoral factor(s), e.g., growth factor(s) [Unsicker et al, 19781, adrenomedullary hormone( s), or extraadrenomedullary hormone(s) [Davis and Hyde, 1966;Smythe et al, 1974;Allain et al, 19861.…”

“…Such different effects among not only different types of cells but also different phases during the 24-h period may be interpreted, at least in part, as the result of matching among several distinct rhythmic and oscillatory biochemical reactions in biochemical networks [ Halberg et al, 19861. In conclusion, we wish to emphasize that various cytophysiological parameters, including mitotic activity in the adrenal medulla, are influenced by pinealectomy, depending on the time of day and type of cells; also, the types of changes that occur following pinealectomy differ depending on these parameters. Although many results indicate that the pineal gland has a role in phase tuning and coordinations of not only intercellular, but also intracellular, relations in the adrenal medulla [Kachi, 1987;Kachi et al, 1979Kachi et al, , 1980aKachi et al, , 1988a, exact mechanisms of pineal actions on adrenomedullary cytophysiological activities remain to be clarified in future experiments.…”