TY - JOUR T1 - Single-unit activity of dorsomedial arcuate neurons and diurnal changes of tuberoinfundibular dopaminergic neuron activity in female rats with neonatal monosodium glutamate treatment. AU - Lin,J Y, AU - Pan,J T, PY - 1999/4/21/pubmed PY - 1999/4/21/medline PY - 1999/4/21/entrez SP - 103 EP - 8 JF - Brain research bulletin JO - Brain Res Bull VL - 48 IS - 1 N2 - Neonatal monosodium glutamate (MSG)-treated rats were used in this study to answer two questions: (1) whether or not the dopamine-responsive dorsomedial arcuate (dm-ARN) neurons are tuberoinfundibular dopaminergic (TIDA) neurons, and (2) whether or not the remaining TIDA neurons in MSG-treated rats are functioning normally. MSG (4 mg/g b. wt., subcutaneously [s.c.]) or saline was given to neonatal Sprague-Dawley rats on days 1, 3, 5, 7, and 9 after birth. The female rats were ovariectomized at 50 days of age and treated with estrogen for 1 week before they were used between 65-90 days of age. The tyrosine hydroxylase-immunoreactive (TH-ir) neurons located in the dm and ventrolateral (vl) parts of the ARN were significantly reduced in MSG-treated rats, as determined by immunohistochemical method. Some TH-ir cells, however, were visible along the border of the third ventricle. Using single-unit recording in brain slices, we found that dopamine inhibited significantly fewer percentage of dm-ARN neurons in MSG-treated (28.2%, n = 39) than in saline-treated rats (73.3%, n = 15). In contrast, bombesin exhibited similar effects (over 70% excitation) in both groups. Using neurochemical means, neonatal MSG treatment produced significant decreases of both 3,4-dihydroxyphenylacetic acid and dopamine levels, but not their ratios, in the median eminence. Moreover, the diurnal change of TIDA neuronal activity persisted in the MSG-treated rats; so did the estrogen-induced afternoon prolactin surge. All these results indicate that neonatal MSG-treatment reduced the number and altered the location of TIDA and dopamine-responsive dm-ARN neurons. The remaining TIDA neurons seemed to be able to maintain their basal activities and diurnal rhythm. SN - 0361-9230 UR - https://www.unboundmedicine.com/medline/citation/10210175/Single_unit_activity_of_dorsomedial_arcuate_neurons_and_diurnal_changes_of_tuberoinfundibular_dopaminergic_neuron_activity_in_female_rats_with_neonatal_monosodium_glutamate_treatment_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0361-9230(98)00153-1 DB - PRIME DP - Unbound Medicine ER -