Regulation of synaptic ribbons in rat pineal gland explants by norepinephrine and sympathetic neurons in a co-culture model.
The hypothesis that synaptic ribbons in the mammalian pinealocyte are influenced by adrenergic mechanisms was tested in the present study using a co-culture model of pineal glands and superior cervical ganglia from neonatal rats. Pineal gland explants survived and showed a high degree of differentiation when cultured for up to 30 days regardless of the presence or absence of superior cervical ganglia. Pineal glands also had neurotrophic properties promoting the survival and neurite extension from superior cervical ganglia. Synaptic ribbons were a common ultrastructural feature in all pineal cultures. There was a significant decline in synaptic ribbon numbers when co-cultured with superior cervical ganglia for both 7 and 30 days. A similar significant decrease in synaptic ribbon frequency was observed after treatment of pineal explants with norepinephrine (10(-5 )M) for both 7 and 30 days. These findings are consistent with the hypothesis that neural mechanisms play an important role in regulating synaptic ribbon numbers, at least during early development. The study also illustrates the utility of pineal gland-superior cervical ganglia co-cultures as a model for future investigations of neuron-target interactions in the pineal.
McNulty
J A
JA
Department of Cell Biology, Neurobiology and Anatomy, Loyola University Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA.
Madsen
T M
TM
Tsai
S Y
SY
Fox
L M
LM
Tonder
N
N
D000818:Animals; D018920:Coculture Techniques; D046508:Culture Techniques; D005260:Female; D007150:Immunohistochemistry; D008297:Male; D008854:Microscopy, Electron; D009474:Neurons / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology*; D010870:Pineal Gland / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D017783:Superior Cervical Ganglion / Q000166:cytology / Q000502:physiology; D017779:Sympathetic Fibers, Postganglionic / Q000502:physiology; D013564:Sympathetic Nervous System / Q000166:cytology / Q000502:physiology*; D013569:Synapses / Q000502:physiology* / Q000648:ultrastructure; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
D014446:Tyrosine 3-Monooxygenase; D009638:Norepinephrine