Daily Rhythmic Changes in Synaptic Vesicle Contents of Nerve Endings on Adrenomedullary Adrenaline Cells, and Their Modification by Pinealectomy and Sham Operations

Abstract

Nerve endings on adrenaline cells in male rat adrenal medullas were investigated by quantitative electron microscopy, with sampling at 8 times during a standard light:dark (12:12) photoperiod. Number (N) per unit area of 2 vesicle types (small clear vesicle, SCV; large granular vesicle, LGV) and % of LGV per total vesicle N were determined. Normal (non-operated) animals showed a circadian rhythm (p < 0.005) in mean SCVN and one with nearly opposite phase relations in %LGVN. Doubly sham-operated animals had a similar rhythm in %LGVN but diminished circadian change in SCVN. Pinealectomized animals had a circadian pattern in SCVN, but this differed from that of normals in having a 2nd peak, a delay or phase shift of the primary peak, and an increased amplitude of the rhythmic changes.

An electron microscopic study on nerve endings on adrenomedullary adrenaline cells in golden hamsters: position, size and changes due to pinealectomy

“…As shown in the results, position, shape, and envelope of preganglionic nerve endings in the adrenal medulla of the golden hamster were similar to the previous description in the rat and the golden hamster (Coupland, 1965;Grynszpan-Winograd, 1974a, b;Kachi et al, 1979Kachi et al, , 1980Kachi et al, , 1993a. But the frequencies of nerve endings in the three portions were shown here for the fi rst time.…”

“…The frequency of nerve endings in the 'follicullar lumen-junctional intercellular part' was highest (>50%), and showed no apparent changes following PX. Therefore, even if activity levels of these nerve endings change following PX, the changed levels are probably reflected, not by positional changes of nerve endings, but by ultrastructural changes such as those in the synaptic vesicle and the invagination complex (Kachi et al, 1979(Kachi et al, , 1980(Kachi et al, , 1988; see also Kachi et al, 1996Kachi et al, , 1998. Nerve endings in this part did not have their envelopes frequently.…”

“…In many of those, the rat, a non-seasonal breeder and non-hibernator, has been used as an experimental animal. Concerning the adrenal medulla, a series of studies on the effects of sham-pinealectomy (SPX) and pinealectomy (PX) on adrenomedullary adrenaline (A) and noradrenaline (NA) cells and nerve endings have been done by us using quantitative LM and EM methods in the rat (Kachi et al, 1979(Kachi et al, , 1980(Kachi et al, , 1988(Kachi et al, , 1993b. In the golden hamster, however, reports on the same subject have been limited to only a few, i.e.…”

“…Basic qualitative and quantitative studies on preganglionic nerve endings in the adrenal medulla at the EM level were done previously, e.g. by Coupland (1965), Grynszpan-Winograd (1974a) and Kachi et al (1979Kachi et al ( , 1993a.…”

Circadian and Ultradian Changes in Synaptic Vesicle Numbers in Nerve Endings on Adrenomedullary Noradrenaline Cells, and Their Modifications by Pinealectomy and Sham Operations

“…Since the animals and general methods were the same as de scribed earlier [17] we will limit our consideration here to features that are essential for understanding and interpreting the results to be reported, and those that differ from what was presented previously.…”