Effects of monosodium L-glutamate on pituitary innervation in goldfish, Carassius auratus.
Monosodium L-glutamate was injected intraperitoneally into goldfish at a dosage of 2.5 mg/g body wt. The first noticeable effect in the pituitary, 30 min postinjection, was marked swelling of pituicytes in the neurohypophysis (NH). Eighteen hours postinjection a large number of degenerating type B fibers were found in the NH of the proximal pars distalis (PPD), while all type A fibers, and type B fibers in other parts of the pituitary, remained unaffected. Because glutamate causes a lesion in the nucleus lateral tuberis (NLT), from the anterior margin of the pituitary stalk through to the posterior end of the nucleus, and a minor lesion in the nucleus preopticus periventricularis, it is likely that the NLT is the origin of the degenerative type B fibers in the proximal NH. The significance of these results is discussed in relation to the neuroendocrine regulation of the pituitary functions in goldfish.
D000818:Animals; D001921:Brain / Q000033:anatomy & histology / Q000187:drug effects; D003530:Cyprinidae / Q000033:anatomy & histology*; D005260:Female; D005971:Glutamates / Q000494:pharmacology*; D006054:Goldfish / Q000033:anatomy & histology*; D008297:Male; D008854:Microscopy, Electron; D009410:Nerve Degeneration / Q000187:drug effects; D009412:Nerve Fibers / Q000187:drug effects*; D009490:Neurosecretory Systems / Q000187:drug effects*; D010902:Pituitary Gland / Q000294:innervation* / Q000648:ultrastructure; D010904:Pituitary Gland, Posterior / Q000294:innervation; D012970:Sodium Glutamate / Q000494:pharmacology*
D005971:Glutamates; D012970:Sodium Glutamate