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Quantitative Ultrastructural Analysis of Differences in Exocytosis Number in Adrenomedullary Adrenaline Cells of Golden Hamsters Related to Time of Day, Pinealectomy, and Intracellular Region
Author(s) -
Kachi T.,
Banerji T. K.,
Quay W. B.
Publication year - 1985
Publication title -
journal of pineal research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 131
eISSN - 1600-079X
pISSN - 0742-3098
DOI - 10.1111/j.1600-079x.1985.tb00644.x
Subject(s) - pinealectomy , exocytosis , photoperiodism , melatonin , endocrinology , medicine , intracellular , pineal gland , membrane , andrology , biology , chemistry , biochemistry
This research analyzed differences mainly in the incidence of exocytotic figures in adrenaline cells (A ‐ cells) in pinealectomized (PX), sham‐operated (SPX), and non‐operated (NO) adult male golden hamsters, with the aim of determining whether these parameters change with the time of day and following pinealectomy, and whether intracellular regional differences exist in such changes. Animals acclimated to a standardized light: dark (LD) 12:12 photoperiod were sacrificed at 11 h after the onset of light (L‐11h) and 1 h after the onset of darkness (D‐1h) (8 animals/group/time) at 28 days postoperation. The adrenal medullas were examined and analyzed morphometrically by electron microscopy. The number of exocytoses per unit length (NEL) and the exocytosis index (a rough index of the number of exocytoses per cell) were measured in PF (perivascular‐space‐facing) and non‐PF plasma membranes. NEL increased from L‐11h (NO: 0.040 ± 0.010, X̄± SE) to D‐1h (0.078 ± 0.012) in all three experimental groups (ANOVA: P < 0.005), showing over fourfold higher levels in PF than in non‐PF membranes. NEL in PF membranes in PX animals showed higher levels than those in NO and SPX animals (P < 0.025), but in non‐PF membranes, no differences owing to time of day or surgery were seen. Exocytosis indices were (1) higher at D‐lh than at L‐llh in all three experimental groups (P < 0.005), (2) similar in PF and non‐PF membranes in control groups, and (3) higher in PF membranes in the PX group than in either non‐PF membranes or PF membranes in control groups. In conclusion, the exocytosis number in A cells changes in relation to time of day, rising in early dark phase, and its rise following pinealectomy can be seen only in PF membranes.