Expression of RFamide-related peptide-3 [RFRP-3] mRNA in dorsomedial hypothalamic nucleus and KiSS-1 mRNA in arcuate nucleus of rat during pregnancy

RFamide-related peptide-3 [RFRP-3] and kisspeptin [KiSS-1] are known to respectively inhibit and stimulate gonadotropin releasing hormone [GnRH] and luteinizing hormone [LH] secretion in rat. The aim of the present study was to evaluate the relative mRNA expression of RFRP-3 and KiSS-1 in the hypothalamus of pregnant rats. In a randomized controlled experimental study, the exact pregnancy day of 18 Sprague-Dawley rats were confirmed using the vaginal smear method and were equally assigned to three groups of days 7, 14 and 21 of pregnancy. Four non-pregnant female rats were ovariectomized and assigned as the control group. All rats were decapitated, and the dorsomedial hypothalamic nucleus [DMH] and the arcuate nucleus [ARC] for detection of KiSS-1 mRNA were separated from their hypothalamus to detect RFRP-3 and KiSS-1 mRNA respectively. Then, their relative expressions were compared between control and pregnant groups using real-time polymerase chain reaction [PCR]. The relative expression of RFRP-3 mRNA in DMH did not change significantly during pregnancy [p>0.01]. However, the relative expression of KiSS-1 mRNA in ARC was at its highest in day 7 of pregnancy and decreased until day 21 of pregnancy [p<0.01]. Decrease in GnRH and LH secretion during the pregnancy of rat may be controlled by constant expression of RFRP-3 mRNA and reduced expression of KiSS-1 mRNA in hypothalamus

Panic-like defensive behavior but not fear-induced antinociception is differently organized by dorsomedial and posterior hypothalamic nuclei of Rattus norvegicus (Rodentia, Muridae)

The hypothalamus is a forebrain structure critically involved in the organization of defensive responses to aversive stimuli. Gamma-aminobutyric acid (GABA)ergic dysfunction in dorsomedial and posterior hypothalamic nuclei is implicated in the origin of panic-like defensive behavior, as well as in pain modulation. The present study was conducted to test the difference between these two hypothalamic nuclei regarding defensive and antinociceptive mechanisms. Thus, the GABA A antagonist bicuculline (40 ng/0.2 µL) or saline (0.9% NaCl) was microinjected into the dorsomedial or posterior hypothalamus in independent groups. Innate fear-induced responses characterized by defensive attention, defensive immobility and elaborate escape behavior were evoked by hypothalamic blockade of GABA A receptors. Fear-induced defensive behavior organized by the posterior hypothalamus was more intense than that organized by dorsomedial hypothalamic nuclei. Escape behavior elicited by GABA A receptor blockade in both the dorsomedial and posterior hypothalamus was followed by an increase in nociceptive threshold. Interestingly, there was no difference in the intensity or in the duration of fear-induced antinociception shown by each hypothalamic division presently investigated. The present study showed that GABAergic dysfunction in nuclei of both the dorsomedial and posterior hypothalamus elicit panic attack-like defensive responses followed by fear-induced antinociception, although the innate fear-induced behavior originates differently in the posterior hypothalamus in comparison to the activity of medial hypothalamic subdivisions.

Effects of bilateral electrolytic lesions of the dorsomedial striatum on motor behavior and spatial learning in rats

The dorsal striatum plays an important role in the control of motor activity and learning processes within the basal ganglia circuitry. Furthermore, recent works have suggested functional differentiation between subregions of the dorsal striatum. The present study examined the effects of bilateral electrolytic lesions of the dorsomedial striatum on motor behavior and learning ability in rats using a series of behavioral tests. 20 male wistar rats were used in the experiment and behavioral assessment were conducted using open field test, rotarod test and 8-arm radial maze. In the open field test, rats with bilateral electrolytic lesions of the dorsomedial striatum showed a normal motor function in the horizontal locomotor activity, while in rearing activity they displayed a statistically significant motor impairment when compared to sham operated group. In the rotarod test, a deficit in motor coordination and acquisition of skilled behavior was observed in rats with bilateral electrolytic lesions of the dorsomedial striatum compared to sham. However, radial maze performance revealed similar capacity in the acquisition of learning task between experimental groups. Our results support the premise of the existence of functional dissociation between the dorsomedial and the dorsolateral regions of the dorsal striatum. In addition, our data suggest that the associative dorsomedial striatum may be as critical in striatum-based motor control

Postnatal Development of Brain Natriuretic Peptide-immunoreactive Neuron in the Hypothalamus of the Rat / 체질인류학회지

Brain natriuretic peptide (BNP) is a neuropeptide, isolated from porcine brain that is homologous with atriopeptin. Magnocellular neurosecretory cells located in the paraventricular nucleus and supraoptic nucleus synthesize and secrete neurohormones. The purpose of this study was to investigate distribution of BNP immunoreactivity throughout the rat hypothalamus from the day of birth to 30 days and adult using immunoperoxidase and immunofluorescent staining. The first BNP immunoreactive neurons appeared in the paraventricular and supraoptic nucleus at P10. In adult, BNP immunoreactivity was widely distributed throughout regions of the hypothalamus including dorsomedial hypothalamic nucleus, ventromedial hypothalamic nucleus, arcuate nucleus and internal layer of median eminence. The intensity of BNP immunoreactivity was weak in almost all hypothalamic nuclei except the paraventricular and supraoptic nuclei. BNP immunoreactivity was first observed in the lateral hypothalamic area at P15. In retrochiasmatic supraoptic nucleus, BNP immunoreactivity was first observed at P20 and remarkably distributed in adult. In the present study, distinct localization of BNP immunoreactivity was in the hypothalamic cell bodies and fibers. Although the role of BNP in the brain is yet to be determined, these results indicate that BNP in the neurons of hypothalamus play important role in the regulation of a variety of neurosecretory functions as a neuromodulator during postnatal development of the hypothalamus.

Postnatal Development of Brain Natriuretic Peptide-immunoreactive Neuron in the Hypothalamus of the Rat / 체질인류학회지

Brain natriuretic peptide (BNP) is a neuropeptide, isolated from porcine brain that is homologous with atriopeptin. Magnocellular neurosecretory cells located in the paraventricular nucleus and supraoptic nucleus synthesize and secrete neurohormones. The purpose of this study was to investigate distribution of BNP immunoreactivity throughout the rat hypothalamus from the day of birth to 30 days and adult using immunoperoxidase and immunofluorescent staining. The first BNP immunoreactive neurons appeared in the paraventricular and supraoptic nucleus at P10. In adult, BNP immunoreactivity was widely distributed throughout regions of the hypothalamus including dorsomedial hypothalamic nucleus, ventromedial hypothalamic nucleus, arcuate nucleus and internal layer of median eminence. The intensity of BNP immunoreactivity was weak in almost all hypothalamic nuclei except the paraventricular and supraoptic nuclei. BNP immunoreactivity was first observed in the lateral hypothalamic area at P15. In retrochiasmatic supraoptic nucleus, BNP immunoreactivity was first observed at P20 and remarkably distributed in adult. In the present study, distinct localization of BNP immunoreactivity was in the hypothalamic cell bodies and fibers. Although the role of BNP in the brain is yet to be determined, these results indicate that BNP in the neurons of hypothalamus play important role in the regulation of a variety of neurosecretory functions as a neuromodulator during postnatal development of the hypothalamus.

The role of dorsomedial hypothalamic nucleus in the cardiovascular responses induced by habenular nucleus stimulation and inhibitory effect of deep peroneal nerve / 中国应用生理学杂志

<p><b>AIM</b>To explore whether dorsomedial hypothalamic nucleus (DMH) is involved in the cardiovascular responses induced by habenular nucleus (Hb) stimulation and inhibitory effect of deep peroneal nerve (DPN) stimulation on above responses or not and to analysis transmitter mechanism.</p><p><b>METHODS</b>Experiments were performed on white male rabbits anesthetised with chloralose and urethan. Experimental data were collected by means of stimulating Hb and DPN, recording arterial blood pressure and ectal electrocardiogram (EECG) and microinjecting transmitter blocker.</p><p><b>RESULTS</b>Prominent pressor and ischemic EECG segment changes were elicited by Hb stimulation (P < 0.01) Microinjecting kynurenic acid into ipsilateral DMH had partial blocking effect on pressor and ischemic EECG-ST segment changes induced by Hb stimulation (P < 0.01). Stimulation of bilateral DPN prominently inhibited the pressor and ischemic EECG-ST changes induced by Hb stimulation (P < 0.01, P < 0.05). Microinjecting naloxone into ipsilateral DMH decreased the inhibitory effect of DPN stimulation on above cardiovascular responses elicited by Hb stimulation (P < 0.01, P < 0.05).</p><p><b>CONCLUSION</b>Glutamic acid receptor in DMH is involved in pressor and ischemic changes induced by Hb stimulation. DMH and opiate peptide receptors in DMH are involved in the inhibitory effect of DPN stimulation on pressor and ischemic changes induced by Hb stimulation.</p>

Location of CNS Labeled Neurons Innervating the Rat Thymus Using the Pseudorabies Virus / 체질인류학회지

This experimental studies was to investigate the location of CNS labeled neurons following injection of pseudorabies virus (PRV), Bartha strain, into the rat thymus. After survival times of 96~120 hours following injection of PRV, the rats were perfused, and their spinal cord and brain were frozen sectioned(30micrometer). These sections were stained by PRV immunohistochemical staining method, and observed with light microscope The results were as follows: 1. The PRV labeled spinal cord segments projecting to the rat thymus were founded in cervical and thoracic segments. Densely labeled areas of each spinal cord segment were founded in lamina V, VII, X, intermediolateral nucleus and dorsal nucleus. 2. In the rhombencephalon, PRV labeled neurons projecting to the thymus were founded in the A1 noradrenalin cells/C1 adrenalin cells/caudoventrolateral reticular nucleus, rostroventro-lateral reticular nucleus, medullary reticular nucleus, area postrema, nucleus solitary tract, nucleus raphe obscurus, nucleus raphe pallidus, nucleus raphe magnus, gigantocellular reticular nucleus, lateral paragigantocellular nucleus and spinal trigeminal nucleus. 3. In the mesencephalon, PRV labeled neurons were founded in parabrachial nucleus, Kolliker-Fuse nucleus, central gray matter, substantia nigra, nucleus dorsal raphe, A8 dopamin cells of retrorubral field, Edinger-Westphal nucleus, locus coeruleus, subcoeruleus nucleus and A5 noradrenalin cells. 4. In the prosencephalon, PRV labeled neurons were founded in reuniens thalamic nucleus, paraventricular thalamic nucleus, precommissural nucleus, paraventricular hypothalamic nucleus, anterior hypothalamic nucleus, lateral hypothalamic nucleus, preoptic hypothalamic nucleus, retrochiasmatic area, arcuate nucleus, dorsomedial hypothalamic nucleus and ventromedial hypothalamic nucleus. These results suggest that PRV labeled neurons of the spinal cord projecting to the rat thymus might be the neurons related to the viscero-somatic sensory and sympathetic preganglionic neurons, and PRV labeled neurons of the brain may be the neurons response to the movement of smooth muscle in blood vessels. These PRV labeled neurons may be central autonomic center related to the integration and modulation of reflex control linked to the sensory system monitoring the internal environment. These observations provide evidence for previously unknown projections from spinal cord and brain to the thymus which may be play an important role in the regulation of thymic function.

Coexistence of Tyrosine Hydroxylase and Nicotinamide Adenine Dinucleotide Phosphate-Diaphorase in Hypothalamic Neurons of the Rat / 대한해부학회지

The presence and coexistence of nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-diaphorase) with tyrosine hydroxylase (TH) was investigated by combining NADPH-diaphorase histochemistry with TH immunohistochemistry in hypothalamic nuclei of the rat. TH-immunoreactive and NADPH-diaphorase positive neurons were found in the medial preoptic area and medial preoptic nucleus, anterior hypothalamic area, dorsomedial hypothalamic nucleus, paraventricular nucleus, supraoptic nucleus and posterior hypothalamic area, respectively. TH and NADPH-diaphorase did not coexist in the anterior hypothalamic area, dorsomedial hypothalamic nucleus, medial preoptic area and posterior hypothalamic area. A considerable portion (30~50%) of the NADPH-diaphorase positive neurons in the supraoptic nucleus colocalized TH. In the medial preoptic area and paraventricular nucleus, some (5~15%) of TH-immunoreactive neurons also contained NADPH-diaphorase activity. NADPH-diaphorase is known to be an indicator of the enzyme nitric oxide synthase; these results therefore suggest that nitric oxide may play an important role in the regulation of the activity of the hypothalamic dopaminergic system of the rat.

Faster gastric emptying of a liquid meal in rats after hypothalamic dorsomedial nucleus lesion

The effects of dorsomedial hypothalamic (DMH) nucleus lesion on body weight, plasma glucose levels, and the gastric emptying of a liquid meal were investigated in male Wistar rats (170-250 g). DMH lesions were produced stereotaxically by delivering a 2.0 mA current for 20 s through nichrome electrodes (0.3-mm tip exposure). In a second set of experiments, the DMH and the ventromedial hypothalamic (VMH) nucleus were lesioned with a 1.0-mA current for 10 s (0.1-mm tip exposure). The medial hypothalamus (MH) was also lesioned separately using a nichrome electrode (0.3-mm tip exposure) with a 2.0-mA current for 20 s. Gastric emptying was measured following the orogastric infusion of a liquid test meal consisting of physiological saline (0.9 percent NaCl, w/v) plus phenol red dye (6 mg/dl) as a marker. Plasma glucose levels were determined after an 18-h fast before the lesion and on the 7th and 15th postoperative day. Body weight was determined before lesioning and before sacrificing the rats. The DMH-lesioned rats showed a significantly faster (P<0.05) gastric emptying (24.7 percent gastric retention, N = 11) than control (33.0 percent gastric retention, N = 8) and sham-lesioned (33.5 percent gastric retention, N = 12) rats, with a transient hypoglycemia on the 7th postoperative day which returned to normal by the 15th postoperative day. In all cases, weight gain was slower among lesioned rats. Additional experiments using a smaller current to induce lesions confirmed that DNH-lesioned rats had a faster gastric emptying (25.1 percent gastric retention, N =7) than control (33.4 percent gastric retention, N = 17) and VMH-lesioned (34.6 percent gastric retention, N = 7) rats. MH lesions resulted in an even slower gastric emptying (43.7 percent gastric retention, N = 7) than in the latter two groups. We conclude that although DMH lesions reduce weight gain, they do not produce consistent changes in plasma glucose levels. These lesions also promote faster gastric emptying of an inert liquid meal, thus suggesting a role for the DMH in the regulation of gastric motility.

Dopaminergic Neurons in the Diencephalon of Striped Field MouseApodemus agrarius coreae / 대한해부학회지

The distributions and morphological characteristics of neurons displaying immunoreactivity to the catecholamine synthetic enzymes, tyrosine hydroxylase[TH], dopamine-beta-hydroxylase[DBH], and phenyletha-nolamine-N-methyltransferase[PNMT] were examined in the adjacent sections of the diencephalon of the striped field mouse [Apodemus agrarius coreae].Only TH-, and no DBH- or PNMT-immunoreactive neurons were found in the diencephalon. In the preoptic area, TH-immunoreactive neurons were found in the anterior preoptic nucleus of Loo[APN], periventricular preoptic nucleus, medial preoptic nucleus, lateral preoptic nucleus and suprachiasmatic nucleus. In the hypothalamus, TH-immunoreactive neurons were found in theparaventricular hypothalamic nucleus, periventricular gray, retrochiasmatic area,anterior hypothalamic nucleus of anterior hypothalamic area and retrochiasmatic region of the hypothalamus. In the rostral tuberal region of the hypothalamus, TH-immunoreactive neurons were found in the paraventricular nucleus, periventricular gray and arcuate nucleus. In the midtuberal region of the hypothalamus, TH-immunoreactive neurons were found in the paraventricular nucleus, dorsomedial hypothalamic nucleus, zona incerta and arcuate nucleus. In the caudal tuberal region of the hypothalamus, dorsal hypothalamic nucleus, posterior hypothalamic complex and arcuate nucleus.