In vivo effect of dopamine antagonists on melanocyte-stimulating hormone cells of the goldfish (Carassius auratus L.) pituitary.
Young goldfish were injected with three dopaminergic antagonists, pimozide, sulpiride, and domperidone, for 5 (low dose) and 7 days (higher dose). Cytological and immunocytochemical techniques using anti-alpha-melanocyte-stimulating hormone (MSH) serum were applied to the pituitary. MSH cells in the three treated groups showed a decrease in immunoreactive cytoplasmic granules, a significant nuclear hypertrophy, and, after 7 days, a cellular enlargement. The nucleolus and the lamellar endoplasmic reticulum were more developed and some mitotic figures occurred. Erythrophores and occasional melanophores were in a stage of maximal dispersion. These changes were not apparent in the solvent-injected controls. The responses to the three blockers of dopaminergic receptors were similar. These data suggest that MSH release seems to be under a dopaminergic inhibitory control in the goldfish. The other cell type of the pars intermedia (PAS-positive and calcium-sensitive in the goldfish) was not clearly affected by the three drugs.
Olivereau
M
M
Laboratoire de Physiologie, Institut Océanographique, Paris, France.
Olivereau
J M
JM
Lambert
J F
JF
D000818:Animals; D003530:Cyprinidae / Q000502:physiology*; D004294:Domperidone / Q000494:pharmacology; D004298:Dopamine / Q000502:physiology*; D018492:Dopamine Antagonists; D006054:Goldfish / Q000502:physiology*; D007150:Immunohistochemistry; D009074:Melanocyte-Stimulating Hormones / Q000378:metabolism*; D010868:Pimozide / Q000494:pharmacology; D010904:Pituitary Gland, Posterior / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D013469:Sulpiride / Q000494:pharmacology
D018492:Dopamine Antagonists; D010868:Pimozide; D004294:Domperidone; D013469:Sulpiride; D009074:Melanocyte-Stimulating Hormones; D004298:Dopamine