TY - JOUR
T1 - A pharmacological analysis of food intake regulation in rats treated neonatally with monosodium L-glutamate (MSG)
AU - Dawson, Ralph
AU - Wallace, David R.
AU - Gabriel, Steven M.
PY - 1989/2
Y1 - 1989/2
N2 - Studies were conducted to examine deficits in food intake regulation in MSG-treated rats that result from known or suspected damage to neurotransmitter systems involved in feeding. Male rats were injected with either MSG (4 mg/g) or sodium chloride on postnatal days 2 and 4 (MSG-Lo) or postnatal days 2, 4, 6 and 8 (MSG-Hi). As adults, MSG-treated and control rats (n = 12/group) were examined for deficits in pharmacologically elicited feeding and other measures of food intake regulation. A second group of MSG-treated (n = 9/group) and control rats (n = 12) were used to measure basal blood pressure and nociceptive reactivity in adulthood. Organ weights, body weight and neuropeptide Y (NPY) content in brain regions were determined at the end of the study. MSG-Hi rats consumed significantly less food than controls during the dark part of the light cycle. Both MSG-Hi and MSG-Lo groups ate significantly less food than controls after a 48-hour fast. MSG-Hi and MSG-Lo rats consumed significantly less food than controls in response to 1.0 mg/kg morphine. MSG-Hi rats consumed significantly less food than controls during the dark phase and significantly more food than controls during the light phase in response to naloxone (1.0 mg/kg). MSG-Lo ate significantly more than controls in response to 0.1 mg/kg guanfacine. MSG-Hi and MSG-Lo showed a significant attenuation in diazepam-stimulated feeding when compared to controls. Blood pressure was significantly lower in both MSG-Hi and MSG-Lo rats compared to controls. Tail flick latencies were not altered by MSG-treatment. Both doses of MSG produced significant reductions in anterior pituitary, testicular, adrenal and kidney weights relative to the controls. NPY content was significantly reduced in the hypothalamus of MSG-treated (Hi and Lo) rats, but not in other brain regions. The relationship between MSG-induced neurotoxicity and the behavioral and neurochemical deficits of MSG-treated rats was discussed.
AB - Studies were conducted to examine deficits in food intake regulation in MSG-treated rats that result from known or suspected damage to neurotransmitter systems involved in feeding. Male rats were injected with either MSG (4 mg/g) or sodium chloride on postnatal days 2 and 4 (MSG-Lo) or postnatal days 2, 4, 6 and 8 (MSG-Hi). As adults, MSG-treated and control rats (n = 12/group) were examined for deficits in pharmacologically elicited feeding and other measures of food intake regulation. A second group of MSG-treated (n = 9/group) and control rats (n = 12) were used to measure basal blood pressure and nociceptive reactivity in adulthood. Organ weights, body weight and neuropeptide Y (NPY) content in brain regions were determined at the end of the study. MSG-Hi rats consumed significantly less food than controls during the dark part of the light cycle. Both MSG-Hi and MSG-Lo groups ate significantly less food than controls after a 48-hour fast. MSG-Hi and MSG-Lo rats consumed significantly less food than controls in response to 1.0 mg/kg morphine. MSG-Hi rats consumed significantly less food than controls during the dark phase and significantly more food than controls during the light phase in response to naloxone (1.0 mg/kg). MSG-Lo ate significantly more than controls in response to 0.1 mg/kg guanfacine. MSG-Hi and MSG-Lo showed a significant attenuation in diazepam-stimulated feeding when compared to controls. Blood pressure was significantly lower in both MSG-Hi and MSG-Lo rats compared to controls. Tail flick latencies were not altered by MSG-treatment. Both doses of MSG produced significant reductions in anterior pituitary, testicular, adrenal and kidney weights relative to the controls. NPY content was significantly reduced in the hypothalamus of MSG-treated (Hi and Lo) rats, but not in other brain regions. The relationship between MSG-induced neurotoxicity and the behavioral and neurochemical deficits of MSG-treated rats was discussed.
KW - Arcuate nucleus
KW - Monosodium L-glutamate
KW - Neuropeptide Y
KW - Neuropharmacology of feeding
KW - Opioids and feeding
KW - α-Adrenoceptor-stimulated feeding
UR - http://www.scopus.com/inward/record.url?scp=0024406067&partnerID=8YFLogxK
U2 - 10.1016/0091-3057(89)90168-8
DO - 10.1016/0091-3057(89)90168-8
M3 - Article
C2 - 2726997
AN - SCOPUS:0024406067
SN - 0091-3057
VL - 32
SP - 391
EP - 398
JO - Pharmacology, Biochemistry and Behavior
JF - Pharmacology, Biochemistry and Behavior
IS - 2
ER -