<b>OBJECTIVEb>To study the cardiovascular effect of selective orexin-1 receptor (OX1R) antagonist SB408124 in anesthetized rats and explore the underlying mechanism by using intracerebroventricular (ICV) microinjection combined with immunohistochemical assay.

<b>METHODSb>The changes of mean arterial blood pressure (MAP) and heart rate (HR) of male Sprague-Dawley rats were recorded during ICV microinjection of SB408124 with or without pretreatment of atropine methyl nitrate or hexamethonium bromide. Furthermore, tyrosine hydroxylase (TH) immunopositive neurons in the rostral ventrolateral medulla (RVLM) of the rat were detected with immunohistochemical assay after ICV microinjection of SB408124.

<b>RESULTSb>ICV administration of SB408124 resulted in a significant decrease in MAP in anesthetized rats, which was accompanied with a mild decrease in HR. The cardiovascular responses elicited by SB408124 were not abolished by pretreatment of atropine methyl nitrate whereas fully abolished by pretreatment of hexamethonium bromide. The number of TH-immunopositive neurons in rat RVLM were significantly decreased following ICV administration of SB408124.

<b>CONCLUSIONb>ICV microinjection of selective OX1R antagonist SB408124 can cause decreases of MAP and HR mediated by inhibiting sympathetic activity in anesthetized rats.

Animals ; Blood Pressure ; drug effects ; Heart Rate ; drug effects ; Male ; Orexin Receptors ; Phenylurea Compounds ; administration & dosage ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Receptors, G-Protein-Coupled ; antagonists & inhibitors ; Receptors, Neuropeptide ; antagonists & inhibitors

The existence of opioid receptors in mammalian cerebellum except human, has not been clearly understood. In the present study, we found that NPY was inducible by morphine in the mouse cerebellar granular and Purkinje cell layers. We performed in situ RT-PCR and immunohistochemistry to characterize the NPY expression. The increase of NPY gene expression by morphine (30 mg/kg, i.p.) was inhibited by pretreatment with not only naloxone (100 mg/kg, i.p.) but also a noncompetitive NMDA antagonist, MK-801 (0.3 mg/kg, i.p.). The competitive NMDA antagonist, AP-5 (0.9 mg/kg, i.p.) slightly attenuated the increased NPY expression by morphine. Also, the finding similar to morphine was shown by NMDA (70 mg/kg, i.p.) treatment. Our results indicate that NPY was inducible by morphine and this might reflect activation of NMDA receptors in granule cells that relay mossy fiber inputs to Purkinje cells via parallel fibers.
Animals ; Cerebellum* ; Dizocilpine Maleate ; Gene Expression ; Humans ; Immunohistochemistry ; Mice* ; Morphine* ; N-Methylaspartate* ; Naloxone ; Negotiating* ; Neuropeptide Y* ; Neuropeptides* ; Purkinje Cells ; Receptors, N-Methyl-D-Aspartate ; Receptors, Opioid

<b>OBJECTIVEb>To examine the changes of expressions of orexin A, orexin receptor-1 (OX1R), prepro-orexin (Prepro-OX) mRNA, OX1R mRNA and ob-R of hypothalamus in rats with chronic renal failure (CRF).

<b>METHODSb>Sixty-two male Wister rats weighing 200-250 g were divided into three groups, including group 1 (normal, n = 5), group 2 (sham-operated, n = 25) and group 3 (CRF, n = 32). Hypothalamus orexin A was assayed by radioimmunoassay. Serum leptin was assayed by enzyme linked immunosorbent assay. The expression of Prepro-OX mRNA and OX1R mRNA of hypothalamus were measured by reverse transcription polymerase chain reaction, and expression of orexin A, OX1R and ob-R by immunohistochemistry. Automatic biochemical analyzer was used to measure the serum creatinine.

<b>RESULTSb>Hypothalamus orexin A levels were negatively correlated (r = -0.63, P < 0.001) with serum leptin levels in the rats. The expression of hypothalamus Prepro-OX mRNA in CRF rats was significantly lower than that of sham-operation at week 12 (P < 0.01). Hypothalamus Prepro-OX mRNA levels were negatively correlated (r = -0.81, P < 0.001) with the levels of serum leptin and serum creatinine (r = -0.68, P < 0.05) in the rats at week 12. The expression of hypothalamus OX1R mRNA in CRF rats was lower than that of sham-operation at week 12 (P > 0.05). Specific immunoreactivity for orexin A was present in perikeryon of the hypothalamus neuron. Specific OX1R-like immunoreactivity was observed in some nerve fibres. Specific immunoreactivity for ob-R was present in membranes of the hypothalamus neuron. Hypothalamus neurons of orexin A-like specific immunoreactivity in CRF rats were significantly fewer than those in shamoperated rats at week 8. Hypothalamus neurons of OX1R-like specific immunoreactivity in CRF rats were similar to those in sham-operated rat at week 8. Hypothalamus neurons of ob-R-like specific immunoreactivity in CRF rats were significantly more than those in sham-operated rats at week 8.

<b>CONCLUSIONSb>The lower hypothalamus orexin A levels may be induced by high serum leptin level in CRF rats. The lower expression of hypothalamus Prepro-OX mRNA in CRF rats may be one of the main causes inducing lower hypothalamus orexin A. The expression of OX1R in hypothalamus neurons is somewhat reduced and the expression of ob-R in hypothalamus neurons is somewhat raised in CRF rats. These remain to be studied further.

Animals ; Carrier Proteins ; genetics ; metabolism ; Hypothalamus ; metabolism ; Intracellular Signaling Peptides and Proteins ; Kidney Failure, Chronic ; metabolism ; Leptin ; genetics ; metabolism ; Male ; Neuropeptides ; genetics ; metabolism ; Neurotransmitter Agents ; genetics ; metabolism ; Orexin Receptors ; Orexins ; Protein Precursors ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Random Allocation ; Rats ; Rats, Wistar ; Receptors, Cell Surface ; genetics ; metabolism ; Receptors, G-Protein-Coupled ; Receptors, Leptin ; Receptors, Neuropeptide ; genetics ; metabolism

<b>OBJECTIVEb>To evaluate the effects of acute glucose level changes on expression of prepro-orexin, orexin 1 receptor (OX1R) and orexin 2 receptor (OX2R) mRNA in rat hypothalamus tissue and pancreatic islets cells.

<b>METHODSb>Thirty adult male Wistar rats were randomly divided into three equal groups (n = 10). The acute hypoglycemia rat model was induced by a single subcutaneous injection of insulin. Twenty acute hypoglycemia rats were divided into group B and group C. Group B was allowed to eat freely, while group C was food-deprived. Control rats were injected the same volume of saline. The effect of glucose levels (2.8 mmol/L and 8.3 mmol/L) on pancreatic islet cell orexin system was detected in pancreas islet cell cultured in vitro. The expression of prepro-orexin and OXR mRNA was examined in rat hypothalamus tissue and pancreatic islets cell cultured in vitro using reverse transcription-polymerase chain reaction (RT-PCR).

<b>RESULTSb>Expression of orexin mRNA increased about 150% for the food-deprived hypoglycemia rats in comparison with control group (P < 0.01), whereas expression of OX1R mRNA decreased up to 30% (P < 0.01). However, expression of OX2R mRNA was unchanged in comparison with control group. In vitro, after incubation with 2.8 mmol/L glucose for 6 hours, the expression of prepro-orexin mRNA increased 2 times in rat pancreas islet cells in comparison with 8.3 mmol/L glucose group (P < 0.01). But the expression of OX1R mRNA was not sensitive to acute glucose fluctuation.

<b>CONCLUSIONSb>Orexin in rat hypothalamus is stimulated by decline in blood glucose and inhibited by signals related to feeding. Moreover, glucose plays a role in modulating the gene expression of prepro-orexin in rat pancreatic islet cells.

Animals ; Blood Glucose ; metabolism ; Glucose ; pharmacology ; Hypoglycemia ; metabolism ; Hypothalamus ; metabolism ; Insulin ; pharmacology ; Intracellular Signaling Peptides and Proteins ; genetics ; Islets of Langerhans ; metabolism ; Male ; Neuropeptides ; biosynthesis ; genetics ; Orexin Receptors ; Orexins ; Protein Precursors ; biosynthesis ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; Random Allocation ; Rats ; Rats, Wistar ; Receptors, G-Protein-Coupled ; Receptors, Neuropeptide ; biosynthesis ; genetics

Animal studies indicate that gonadal steroids have prominent neuroprotective effects in several models of experimental traumatic brain injury (TBI). Neuromedin U (NMU) and neuromedin S (NMS) are regulatory peptides involved in inflammatory and stress responses, and modulation of the gonadotropic axis. Since steroid hormone levels change during the estrous cycle, we sought to determine whether variations in ovarian hormones would affect blood-brain barrier (BBB) permeability and brain levels of NMS, NMU, and neuromedin S receptor 2 in experimental TBI. Two groups (proestrus and nonproestrus) of female rats underwent diffuse TBI. At 24 hrs after TBI, results showed a significantly decrease in BBB permeability in traumatic-proestrus animals (TBI-P) in comparison to traumatic nonproestrus (TBI-NP) rats. Western blot analyzes demonstrated an enhanced expression of prepro-NMS in TBI-P compared with that in the TBI-NP group. Likewise, TBI-P rats exhibited significantly higher NMUR2 gene expression compared with those of TBI-NP, whereas no significant difference in brain NMU content was seen between sham and traumatic animals. Our findings indicate that diffuse TBI induces an increase in prepro-NMS and neuromedin S receptor 2 expression in traumatic-proestrus rats which may mediate the anti-edematous effects of gonadal hormones in proestrus rats following trauma.
Neuropeptides ; Receptors, Neuropeptide

The homologous regulation of pituitary Gonadotropin Releasing Hormone Receptor (GnRH-R) mRNA expression by GnRH has been well demonstrated. However, the regulation of the ovarian GnRH-R is poorly understood. The present study was performed to demonstrate the presence of GnRH transcripts in addition to GnRH-R mRNA and the regulation of GnRH-R mRNA expression in the granulosa cells isolated from small antral follicles. The GnRH and GnRH-R mRNA levels were determined by a competitive reverse transcription-polymerase chain reaction (RT-PCR). The granulosa cells were obtained from immature rats implanted with diethylstilbestrol for 3 days. When GnRH transcript expression was examined in isolated granulosa cells by RT-PCR, the PCR products showed two bands. The larger band contained intronic sequences and the smaller band was a fully processed GnRH gene transcript identical to hypothalamic GnRH. This suggests that authentic GnRH gene transcripts are expressed in ovarian granulosa cells and may act on the granulosa cells in a paracrine or autocrine manner. Since GnRH action in the granulosa cells is mediated by specific GnRH-R, it is of interest to examine whether GnRH-R is synthesized in the granulosa cells. When the granulosa cells were cultured in media only, GnRH-R mRNA levels increased abruptly within 3 h and gradually decreased thereafter during the 24 h culture period. However, GnRH itself did not alter the GnRH-R mRNA expression levels in cultured granulosa cells. Interestingly, treatment with FSH decreased the GnRH-R mRNA levels in a dose-dependent manner. A time-course analysis revealed that the GnRH-R mRNA levels were significantly lower up to 9 h after FSH treatment, and returned to the basal level between 12 h-24 h. Activation of adenylate cyclase with forskolin also decreased the GnRH-R mRNA levels. It is therefore concluded that in the granulosa cells of the small antral follicles GnRH-R mRNA expression was not homologously regulated by GnRH, while FSH may negatively regulate GnRH-R mRNA expression in the granulosa cells possibly through a cAMP-protein kinase A pathway.
Animal ; Cells, Cultured ; FSH/pharmacology ; Female ; Gene Expression Regulation* ; Gonadorelin/pharmacology ; Granulosa Cells/metabolism* ; Granulosa Cells/drug effects ; RNA, Messenger/metabolism* ; Rats ; Rats, Sprague-Dawley ; Receptors, LHRH/genetics* ; Reverse Transcriptase Polymerase Chain Reaction

Van Wyk-Grumbach Syndrome is an advanced sexual development in association with primary hypothyroidism. The clinical feature in this syndrome is more consistent with stimulation of the FSH receptor by the markedly elevated TSH levels. Treatment of the hypothyroidism results in a rapid return to normal of the biochemical and clinical manifestations. We experienced a case of Van Wyk-Grumbach Syndrome and report with the brief review of related literature.
Hypothyroidism ; Puberty, Precocious ; Receptors, FSH ; Sexual Development

OBJECTIVE: This study was performed to determine whether the FSH receptor mutation is present in infertile Korean patients with 46,XX premature ovarian failure (POF) women. METHODS: The variant of FSH receptor exon 10 in thirteen 46, XX idiopathic POF and 4 healthy fertile (control) women were studied. Missense mutation in Exon 10 was detected in POF patients and healthy fertile women by polymerase chain reaction-single stranded conformation polymorphism (PCR-SSCP). RESULTS: The variant types of FSH receptor exon 10 (Thr307Ala; A919G) were found in healthy fertile (control) and POF women. CONCLUSIONS: This mutation may not be specific in POF patients and further study is needed in fertile (control) and POF women.
Exons* ; Female ; Humans ; Mutation, Missense ; Primary Ovarian Insufficiency* ; Receptors, FSH*

To directly test if elevated glucocorticoids are required for fasting-induced regulation of growth hormone (GH)-releasing hormone (GHRH), GHRH receptors (GHRH-R) and ghrelin receptors (GHS-R) expression, male rats were bilaterally adrenalectomized or sham operated. After 7 days, animals were fed ad libitum or fasted for 48 h. Bilateral adrenalectomy increased hypothalamic GHRH to 146% and decreased neuropeptide Y (NPY) mRNA to 54% of SHAM controls. Pituitary GHRH-R and GHS-R mRNA levels were decreased by adrenalectomy to 30% and 80% of sham-operated controls. In sham- operated rats, fasting suppressed hypothalamic GHRH (49%) and stimulated NPY (166%) mRNA levels, while fasting increased pituitary GHRH-R (391%) and GHS-R (218%) mRNA levels. However, in adrenalectomized rats, fasting failed to alter pituitary GHRH-R mRNA levels, while the fasting-induced suppression of GHRH and elevation of NPY and GHS-R mRNA levels remained intact. In fasted adrenalectomized rats, corticosterone replacement increased GHRH-R mRNA levels and intensified the fasting-induced decrease in GHRH, but did not alter NPY or GHS-R response. These data suggest that elevated glucocorticoids mediate the effects of fasting on hypothalamic GHRH and pituitary GHRH-R expression, while glucocorticoids are likely not the major determinant in fasting-induced increases in hypothalamic NPY and pituitary GHS-R expression.
Adrenalectomy ; Animals ; Corticosterone ; Fasting ; Glucocorticoids ; Growth Hormone ; Humans ; Male ; Neuropeptide Y ; Rats ; Receptors, Ghrelin ; Receptors, Neuropeptide ; Receptors, Pituitary Hormone-Regulating Hormone ; RNA, Messenger ; Salicylamides

Multicystic ovary was first described by Silver in 1958 as a rare case feature of acquired primary hypothyroidism. In 1980, Lindsay reported four girls with hypothyroidism associated with multicystic ovary diagnosed by pelvic ultrasonography. The mechanism of ovarian cyst formation and pseudoprecocious puberty in severe hypothyroidism in childhood are unknown. Increased ovarian sensitivity to GnRH and increased TSH level which acts on FSH receptor is one of the mechanism explained. We report a case of a girl with primary hypothyroidism presented with pseudoprecocious puberty and giant follicular ovarian cyst with torsion.
Adolescent ; Female ; Gonadotropin-Releasing Hormone ; Humans ; Hypothyroidism* ; Ovarian Cysts* ; Ovary ; Puberty ; Receptors, FSH ; Silver ; Ultrasonography