Differential trophic effects of ORG 2766, an ACTH(4-9)/MSH(4-9) analogue, on peptidergic neurons and glial cells in the snail Lymnaea stagnalis.
Cerebral ganglia of the pond snail Lymnaea stagnalis were incubated in vitro in 10(-6) M ORG 2766 for 10 and 20 h, with or without regular refreshment of the medium. Quantitative ultrastructural study of cross sections of the cerebral commissure showed that the number of microtubules in large axons of all ORG 2766-treated groups had increased after 10 h by approximately 40%. In a separate experiment, central nervous systems were incubated in ORG 2766 for only 15 min and then kept in Ringer's for 9 h and 45 min. Maximal stimulation (40% increase of microtubules) in these specimens was also observed. The results would seem to support the hypothesis that ORG 2766 binds to a receptor and initiates a long-lasting effect. It is argued that ORG 2766 stimulates novel synthesis of tubulin rather than being involved in the assembly of microtubules. Also, glial cells were found to be activated by ORG 2766. This was concluded from the fact that the number of heterochromatin clumps and the size of the clumps in these cells had decreased and the amount of glial tissue surrounding the axons had increased (approximately 50%). In contrast to the activating effects of ORG 2766 on glial tissue, this drug did not affect nucleoli, number, and size of the heterochromatin clumps and the Golgi apparatus in the neuropeptidergic caudodorsal cells. The data indicate that ORG 2766 exerts differential trophic effects.
Postgraduate School of Neurosciences Amsterdam, Faculty of Biology, Section of Histology, The Netherlands.
L J
LJ
Müller
B
B
Kiburg
C M
CM
Moorer-van Delft
H H
HH
Boer
D000324:Adrenocorticotropic Hormone / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000648:ultrastructure; D002466:Cell Nucleolus / Q000187:drug effects; D002843:Chromatin / Q000187:drug effects; D006056:Golgi Apparatus / Q000187:drug effects; D008195:Lymnaea / Q000187:drug effects; D008870:Microtubules / Q000187:drug effects; D009414:Nerve Growth Factors / Q000494:pharmacology*; D009457:Neuroglia / Q000187:drug effects* / Q000648:ultrastructure; D009474:Neurons / Q000187:drug effects* / Q000648:ultrastructure; D009479:Neuropeptides / Q000096:biosynthesis* / Q000378:metabolism; D010446:Peptide Fragments / Q000494:pharmacology*
D002843:Chromatin; D009414:Nerve Growth Factors; D009479:Neuropeptides; D010446:Peptide Fragments; C013765:Org 2766; D000324:Adrenocorticotropic Hormone