Day-night differences in the vesicle populations of nerve terminals in the rat and chick pineal gland.
Day-night differences in the ultrastructure of pineal neuronal elements were quantitated in the rat and the chick--two species that exhibit important differences in adrenergic control of melatonin synthesis. Area densities of small clear vesicles (40-60 nm) and small dense-cored vesicles (40-60 nm) in nerve terminals were significantly reduced during the night in the rat. In the chick, there were no day-night differences in the frequency of clear vesicles, but the number of small dense-cored vesicles tended to be greater at night. There was no effect of day-night sampling on area densities of large dense-cored vesicles (80-120 nm) in either species. These findings are consistent with biochemical evidence for day-night species differences in the adrenergic control of pineal function.
LaPorte
R
R
Department of Anatomy, Loyola University Stritch School of Medicine, Maywood, Ill.
Fox
L M
LM
Mosher
K
K
Binkley
S
S
McNulty
J A
JA
D000818:Animals; D002645:Chickens; D008297:Male; D008854:Microscopy, Electron; D009474:Neurons / Q000648:ultrastructure*; D010507:Periodicity; D010870:Pineal Gland / Q000648:ultrastructure*; D051381:Rats; D011919:Rats, Inbred Strains