Differential sensitivity of hypothalamic and medullary opiocortin and tyrosine hydroxylase neurons to the neurotoxic effects of monosodium glutamate (MSG).
The distribution of opiocortin- (OP-ir) and tyrosine hydroxylase-immunoreactive (TH-ir) perikarya was examined immunocytochemically in rats treated neonatally with the neurotoxin monosodium glutamate (MSG). While OP-ir and TH-ir perikarya were eliminated in the arcuate nucleus in treated animals, the OP-ir and TH-ir cell groups of the nucleus tractus solitarius and contiguous medullary regions were unaffected. This selective elimination of arcuate neurons permitted us to examine specifically the fiber projections of the medullary OP-ir perikarya in treated animals. This revealed a preferential distribution of delicate fibers originating in NTS, to discrete medullary and pontine areas. In control animals, these same terminal fields appeared to be more densely populated with an additional population of thicker OP-ir fibers, suggesting the possibility of a shared innervation of these brainstem regions by both hypothalamic and medullary OP-ir neurons.
D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000473:pathology; D005971:Glutamates / Q000633:toxicity*; D006651:Histocytochemistry; D007028:Hypothalamic Hormones / Q000378:metabolism*; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism*; D008526:Medulla Oblongata / Q000187:drug effects / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D009498:Neurotoxins; D009928:Organ Specificity; D010907:Pituitary Hormones / Q000378:metabolism*; D011333:Pro-Opiomelanocortin; D051381:Rats; D011919:Rats, Inbred Strains; D012970:Sodium Glutamate / Q000633:toxicity*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*
D005971:Glutamates; D007028:Hypothalamic Hormones; D009498:Neurotoxins; D010907:Pituitary Hormones; D011333:Pro-Opiomelanocortin; D014446:Tyrosine 3-Monooxygenase; D012970:Sodium Glutamate