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Acute and long lasting neurochemical effects of monosodium glutamate administration to mice
Abstract:
Acute administration of excitatory amino acids alters the release of anterior pituitary hormones. The neurochemical effects of monosodium glutamate (MSG) administration to adult mice were examined 30 minutes and 60 days after an acute injection (4 mg/g). The permanent effects of an acute injection of MSG were limited to a slight loss of neurons in the ventral arcuate nucleus and a 21% reduction in hypothalamic 5-HIAA levels. Thirty minutes after MSG administration hypothalamic DA and DOPAC levels were increased 27% and 25%, respectively and MOPEG levels were increased 75% in the hypothalamus and 34% in the remaining whole brain. These findings show that the acute administration of MSG results in alterations in hypothalamic monoamine metabolism which may be related to the neuroendocrine consequences of excitatory amino acid administration.
Insights
Acute monosodium glutamate (MSG) administration alters hypothalamic monoamine metabolism and causes minor neuronal loss. These neurochemical changes in the brain may link to neuroendocrine effects.
Area of Science:
- Neuroendocrinology
- Neurochemistry
- Neuropharmacology
Background:
- Excitatory amino acids, like monosodium glutamate (MSG), can influence anterior pituitary hormone release.
- Understanding the neurochemical impact of MSG is crucial for comprehending its neuroendocrine effects.
Purpose of the Study:
- To investigate the neurochemical consequences of acute monosodium glutamate (MSG) administration in adult mice.
- To determine the short-term (30 minutes) and long-term (60 days) effects of MSG on hypothalamic monoamine levels.
Main Methods:
- Adult mice received an acute injection of monosodium glutamate (MSG) at a dose of 4 mg/g.
- Hypothalamic levels of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), 5-hydroxyindoleacetic acid (5-HIAA), and 3-methoxy-4-hydroxyphenylglycol (MOPEG) were measured.
- Neuronal counts in the ventral arcuate nucleus were assessed.
Main Results:
- Thirty minutes post-MSG, hypothalamic DA and DOPAC increased by 27% and 25%, respectively.
- Hypothalamic MOPEG levels rose by 75%, with a 34% increase in the whole brain.
- Long-term effects included a slight loss of neurons in the ventral arcuate nucleus and a 21% reduction in hypothalamic 5-HIAA.
Conclusions:
- Acute MSG administration significantly alters hypothalamic monoamine metabolism.
- These neurochemical alterations may underlie the neuroendocrine effects observed after excitatory amino acid exposure.
- Long-term consequences are subtle, involving minor neuronal loss and reduced 5-HIAA levels.