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Although interleukin (IL)-1 beta activates the hypothalamic-pituitary-adrenal (HPA) axis, the mechanisms by which peripheral IL-1 beta acutely stimulates adrenocorticotropin (ACTH) secretion are not clear. Recently, the vagus has been implicated in mediating peripheral cytokine signalling of the brain. To investigate a possible central mechanism for(More)
The postcastration LH response is greater and somewhat more rapid in male than female rats. We have previously demonstrated that hypothalamic gamma-aminobutyric acid (GABA)ergic neuronal activity decreases following gonadectomy in male rats. To investigate whether these same hypothalamic GABA neurons decrease their activity postcastration in female rats,(More)
We examined the effects of electrical stimulation (ES) of right A1 noradrenergic cells on temporal changes in tyrosine hydroxylase (TH) mRNA levels in A1, A2 and locus ceruleus (LC) neurons by in situ hybridization histochemistry and quantitative image analysis methods. The stimulation parameters used previously have been shown to increase hypothalamic(More)
GABAergic neurons are estimated to make up more than half of the neuronal population of the hypothalamus and they likely account for some of the structural and functional sexual dimorphisms observed in the mammalian brain. We previously reported sex differences in the rate of GABA turnover in discrete hypothalamic structures of adult rats. In the present(More)
Temporal changes in tyrosine hydroxylase (TH) mRNA levels in medullary A1 and A2 neurons and locus coeruleus (LC) cells were studied 6, 12 and 24 h following orchidectomy in rats. Brains from intact controls and sham castrated rats also were evaluated at these same time periods. In situ hybridization histochemistry and quantitative image analysis techniques(More)
These studies determined whether endogenous gamma-aminobutyric acid (GABA) secretion affects LHRH neuronal responsiveness to norepinephrine (NE). The intracerebroventricular (icv) infusion of either bicuculline or phaclofen (GABA-A or GABA-B receptor antagonists, respectively) into ovariectomized (OVX) estrogen-treated rats did not affect basal LH levels(More)
Respiratory colonization of preterm infants with Ureaplasma urealyticum is a significant risk factor for bronchopulmonary dysplasia, a chronic lung disease characterized by arrest of alveolar development, variable interstitial fibrosis, and disordered elastic fibers in the distal airspaces. As indicated in previous studies, moderate to severe fibrosis is a(More)
In these studies we examined the temporal effects of intracerebroventricular (i.c.v.) infusions of norepinephrine (NE) on plasma LH and on LHRH mRNA levels in the organum vasculosum of the lamina terminalis (OVLT) and in neurons located in the rostral (r), middle (m) and caudal (c) preoptic areas (POA) of ovariectomized, estrogen-treated rats. Thereafter,(More)
Some axon terminals of hypothalamic opiate neurons directly synapse on luteinizing hormone-releasing hormone (LHRH) neurons. To determine whether such synaptic connections affect LHRH neuronal activity, we have examined the profiles and concentrations of LH released in response to intracerebroventricular (icv) norepinephrine (NE, 45 μg) infusions alone or(More)
Norepinephrine (NE) turnovers (an index of secretion) increase in the hypothalamus of proestrous rats concomitant with luteinizing hormone surges, whereas, neither of these events are observed in diestrous nor in androgen-sterilized rats. Increased hypothalamic NE release may occur as a consequence of the withdrawal of local inhibitory γ-aminobutyric acid(More)