• The Journal of Korean Medicine
• /
• v.18 no.1
• /
• pp.58-71
• /
• 1997

In order to the location and local arrangement of nerve cell bodies and nerve fibers projecting to the meridian points related to facial nerve paralysis in the rat using the neural tracers, CTB and WGA-HRP, labeled neurons the were investigated by immunohistochemical and HRP histochemical methods following injection of 2.5% WGA-HRP and 1% CTB into Hyopko$(S_6)$. Chichang$(S_4)$, Sugu$(GV_{26})$, Sajukkong$(TE_{23})$ and Yangbaek$(G_{14})$. Following injection of Hyopko$(S_6)$, Chichang$(S_4)$, labeled motor neurons were founded in facial nucleus, trigeminal motor nucleus, reticular nucleus and hypoglossal nucleus. labeled sensory neurons were founded in trigeminal ganglia and $C_{1-2}$ spinal ganglia. sympathetic motor neurons were found in superior cervical ganglia. Sensory fibers labeled in brainstem were found in mesencephalic trigeminal tract, sensory root of trigeminal nerve, oral, interpolar and caudal part of trigeminal nucleus, area postrema, nucleus tractus solitarius, lateral reticular nucleus and $C_{1-2}$ spinal ganglia. Following injection of Sugu$(GV_{26})$, labeled motor neurons were founded in facial nucleus. Labeled sensory neurons were founded in trigeminal ganglia and $C_{1-2}$ spinal ganglia. Sympathetic motor neurons were found in superior cervical ganglia. Sensory fibers labeled in brainstem were found in spinal trigeminal tract, trigeminal motor nucleus, mesencephalic trigeminal tract, oral. interpolar and caudal parts of trigeminal nucleus, area postrema, nucleus tractus solitarius, lateral reticular nucleus, dorsal part of reticular part and $C_{1-2}$ spinal ganglia. Following injection of Sajukkong$(TE_{23})$ and Yangbaek$(G_{14})$, labeled motor neurons were founded in facial nucleus, trigeminal motor nucleus. Labeled sensory neurons were founded in trigeminal ganglia and $C_{1-2}$ spinal ganglia. sympathetic motor neurons were found in superior cervical ganglia. Sensory fibers labeled in brainstem were found in oral, interpolar and caudal parts of trigeminal nucleus, area postrema, nucleus tractus solitarius, inferior olovary nucleus, medullary reticular field and lamina I-IV of $C_{1-2}$ spinal cord. Location of nerve cell body and nerve fibers projecting to the meridian points related to the facial nerve paralysis in the rats were found in facial nucleus and trigeminal motor nucleus. Sensory neurone were found in trigeminal ganglia and $C_{1-2}$ spinal ganglia. Sympathetic motor neurons were found in superior cervical ganglia. Sensory fibers labeled in brainstem were found in mesencephalic trigeminal tract, oral, interpolar and caudal parts of trigeminal nucleus, area postrema, nucleus tractus solitarius. lateral reticular nucleus, medullary reticular field.

• The Korean Journal of Physiology and Pharmacology
• /
• v.4 no.4
• /
• pp.275-281
• /
• 2000

Cholecystokinin (CCK) is a gastrointestinal hormone which plays an important role in satiety and gastric motility. It is also widely distributed throughout the central nervous system, where it appears to be involved in the central control of anxiety, feeding behavior and nociception. Two distinct CCK receptor types, $CCK_A$ and $CCK_B,$ have been found in the brain. Both CCK receptors coexist in the rat nucleus tractus solitarius (NTS), which is the primary center for the coordination of peripheral and central activities related to gastrointestinal, cardiovascular and respiratory functions. In order to study ionic actions of CCK on each type of receptor, we investigated the effects of CCK-8S on neurons located in the NTS of the rat using whole-cell patch-clamp recordings in brainstem slices. Application of CCK-8S, under current clamp, produced a membrane depolarization accompanied by action potential firing. This CCK-evoked excitation was dose-dependent $(10\;nM{\sim}10\;{\mu}M)$ and observed in more than 60% of NTS neurons. Under voltage clamp conditions, CCK-8S induced an inward current with a notably increased spontaneous excitatory synaptic activity. However, CCK-8S did not significantly change the amplitude of pharmacologically isolated and evoked EPSP(C)s. Using selective $CCK_A$ and $CCK_B$ receptor antagonists, we observed two different effects of CCK-8S, which suggest $CCK_A$ receptor-mediated inhibitory and $CCK_B$ receptor-mediated excitatory effects in the NTS. These results may help to explain the ability of CCK to modulate gastrointestinal and other reflex systems in the NTS.

• International Journal of Oral Biology
• /
• v.30 no.3
• /
• pp.91-98
• /
• 2005

Gamma-aminobutyric acid (GABA) is known as an inhibitory neurotransmitter in the neurons of the central nervous system. However, its detailed action mechanisms in the rostral gustatory zone of the nucleus tractus solitarius (rNTS) have not been established. The present study was aimed to investigate the distribution, role and action mechanisms of GABA in rNTS. Membrane potentials were recorded by whole cell recordings in isolated brain slices of the rat medulla. Superfusion of GABA resulted in a concentration-dependent reduction in input resistance in the neurons in rNTS. The change in input resistance ws accompanied by response to a depolarizing pulse were diminished by GABA. Superfusion of the slices with either $GABA_A$ agonist, muscimol, $GABA_B$ agonist, baclofen or $GABA_C$ agonist, TACA, decreased input resistance and reduced the nerve activity in association with membrane hyperpolarization. It is suggested that inhibitory signals playa role in sensory processing by the rNTS, in that GABA actions occur through activation of $GABA_A,\;GABA_B\;and\;GABA_C$ receptor. These results suggest that GABA has an inhibitory effect on the rNTS through an activation of $GABA_A,\;GABA_B\;and\;GABA_C$ receptors and that the GABAergic inhibition probably plays an important role in sensory processing by the rNTS.

• Korean Journal of Veterinary Research
• /
• v.37 no.3
• /
• pp.479-487
• /
• 1997

The present study was carried out to localize the central nuclei innervating the rat colon using pseudorabies virus-Bartha strain which has been known as a very useful neurotracer. The results were as follows. The central nuclei innervating the proximal colon were premotor area, subfornical organ, preoptic area in telencephalon, and paraventricular nucleus, bed nucleus of stria terminalis, retrochiasmatic area in the diencephalon, and periaqueductal gray, Edinger-Westphal nucleus, tegmental nucleus in the mesencephalon, and parabrachial nucleus, locus ceruleus, A5 area, $K{\ddot{o}}lliker$-Fuse nucleus, magnocellular reticular nucleus in the metencephalon, and nucleus tractus solitarius, A1 noradrenergic cell group, dorsal motor nucleus of vagus nerve, nucleus ambiguus, area postrema in the myelencephalon. In the spinal cord, the thoracic division had some nuclei innervating the proximal colon. The nuclei innervating the distal colon were paraventricular nucleus of the diencephalon, Edinger-Westphal nucleus of midbrain, and parabrachial nucleus, locus ceruleus, A5 area, $K{\ddot{o}}lliker$-Fuse nucleus, magnocellular reticular nucleus of the metencephalon, and nucleus tractus solitarius, dorsal motor nucleus of vagus nerve, nucleus ambiguus, area postrema in the myelencephalon. In the spinal cord, thoracic, lumbar and sacral division innervated the distal colon.

• The Korean Journal of Physiology and Pharmacology
• /
• v.8 no.1
• /
• pp.7-15
• /
• 2004

Nitric oxide (NO) system has been implicated in a wide range of physiological functions in the nervous system. However, the role of NO in regulating the neural activity in the gustatory zone of nucleus tractus solitarius (NTS) has not been established. The present study was aimed to investigate the role of NO in the gustatory NTS neurons. Sprague-Dawley rats, weighing about 50 g, were used. Whole cell patch recording and immunohistochemistry were done to determine the electrophysiological characteristics of the rostral gustatory nucleus of the tractus solitaries and distribution of NO synthases (NOS). Neuronal NOS (nNOS) immunoreactivity was strongly detected along the solitary tract extending from rostral to caudal medulla. Resting membrane potentials of NTS neurons were $-49.2{\pm}2\;mV$ and action potential amplitudes were $68.5{\pm}2\;mV$ with a mean duration measured at half amplitude of $1.7{\pm}0.3\;ms$. Input resistance, determined from the response to a 150 ms, -100 pA hyperpolarizing current pulse, was $385{\pm}15\;M{\Omega}$, Superfusion of SNAP or SNP, NO donors, produced either hyperpolarization (68%), depolarization (5%), or no effect (27%). The hyperpolarization was mostly accompanied by a decrease in input resistance. The hyperpolarization caused by SNAP or SNP increased the time to initiate the first action potential, and decreased the number of action potentials elicited by current injection. SNP or SNAP also markedly decreased the number of firing neural discharges of the spontaneous NTS neural activity under zero current. Superfusion of L-NAME, a NOS inhibitor, slightly depolarized the membrane potential and increased the firing rate of NTS neurons induced by current injection. ODQ, a soluble guanylate cyclase inhibitor, ameliorated the SNAP-induced changes in membrane potential, input resistance and firing rates. 8-Br-cGMP, a non-degradable cell-permeable cGMP, hyperpolarized the membrane potential and decreased the number of action potentials. It is suggested that NO in the gustatory NTS has an inhibitory role on the neural activity of NTS through activating soluble guanylate cyclase.

• The Korean Journal of Physiology and Pharmacology
• /
• v.18 no.4
• /
• pp.353-358
• /
• 2014

Control of blood pressure is maintained by the interaction between the arterial baroreflex and vestibulosympathetic reflex during postural changes. In this study, the contributions of vestibular receptors and baroreceptors to the maintenance of blood pressure following acute hypotension were compared in terms of phosphorylated extracellular regulated protein kinase (pERK) expression in the nucleus tractus solitaries (NTS). Expression of pERK in the NTS was measured in conscious rats that had undergone bilateral labyrinthectomy (BL) and/or sinoaortic denervation (SAD) 5, 10, 20, and 40 min following acute hypotension induced by sodium nitroprusside (SNP) infusion. Expression of pERK increased significantly in the NTS in the control group following SNP infusion, and the expression peaked at 10 min after SNP infusion. The number of pERK positive neurons increased following SNP infusion in BL, SAD, and BL+SAD groups, although the increase was smaller than in control group. The BL group showed a relatively higher reduction in pERK expression than the SAD group, and the pERK expression in the NTS was localized to the caudal portion of the nuclei in the BL and SAD groups. These results suggest that the vestibular receptors may play a key role in maintaining blood pressure following acute hypotension; thus, the vestibular system may contribute to compensate for orthostatic hypotension.

• Journal of Acupuncture Research
• /
• v.20 no.6
• /
• pp.89-102
• /
• 2003

Objective: The expression of CRF(corticotropin releasing factor), CRF-R(receptor) and CRF-BP(binding protein) in CNS neurons projecting to the stomach and ST36 using the pseudorabies virus in the rat was investigated. Methods: After survival times of 5 days following injection of PRV-Ba-Gal, The thirty rats were perfused, and their brain were frozen sectioned($30{\mu}m$). These sections were stained by PRV-Ba-Gal histochemical staining method and(or) CRF, CRF-R and CRF-BP immunohistochemical method. The common expressed areas of the brain projecting to the stomach and zusanli(ST36) following injection of PRV-Ba-Gal were observed with light microscope. Results: 1) The dense accumulation of CRF-immunoreactive terminals is seen in the area postrema, n. tractus solitarius, external zone of the median eminence, with some immunoreactive CRF also present in the internal zone. 2) Aggregates of CRF-R immunoreactive perikarya are found in area postrema, n. tractus solitarius, lateral reticular n., gigantocellular reticular n., locus coeruleues, paraventricular n. of hypothalamus, median eminence, preoptic n., arcuate n. and hind limb area of cerebral cortex. 3) Aggregates of CRF-BP immunoreactive perikarya are found in area postrema, n. tractus solitarius, lateral reticular nucleus, gigantocellular reticular n., locus coeruleues, paraventricular n. of hypothalamus, median eminence and arcuate n.. Conclusions : These results suggest that PRV-Ba-Gal labeled areas projecting to stomach and ST36 may be related to the central autonomic pathways. A part of CNS neurons projecting to the stomach and ST36 were related to expression of CRF, CRF-R and CRF-BP related to the stress in central autonomic center.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.23 no.4
• /
• pp.805-817
• /
• 2009

This study was to investigate central localization of neurons projecting to the urinary bladder and urinary bladder-related acupoints(Wijung, $BL_{40}$) and neurons of immunoreactive to hormones and hormone receptors regulating urinary bladder function by using peudorabies virus(PRV). In this experiment, Bartha's strain of pseudorabies virus was used in rats to trace central localization of urinary bladder-related neurons and urinary bladder-related acupoints($BL_{40}$) which can regulate urinary system. PRV was injected into the urinary bladder and acupoints($BL_{40}$) related urinary system. After six days survival of rats, mainly common labeled neurons projecting to the urinary bladder and urinary bladder-related acupoints were identified in spinal cord, medulla, pons and diencephalon by PRV immunohistochemical staining method. First-order PRV labeled neurons projecting to urinary bladder and urinary bladder-related acupoints were found in the cervical, thoracic, lumbar and sacral spinal cord. Commonly labeled preganglionic neurons were labeled in the lumbosacral spinal cord and thoracic spinal cord. They were found in the lateral horn area(sacral parasympathetic nucleus and intermediolateral nucleus), lamina V-X, intermediomedial nucleus and dorsal column area. The area of sensory neurons projecting to urinary bladder and Wijung($BL_{40}$) was L5-S2 spinal ganglia and T12-L1 spinal ganglia, respectively. In the brainstem, the neurons were labeled most evidently and consistently in the nucleus of tractus solitarius, area postrema, dorsal motor nucleus of vagus nerve, reticular nucleus, raphe nuclei(obscurus, magnus and pallidus), C3 adrenalin cells, parapyramidal area(lateral paragigantocellular nucleus), locus coeruleus, subcoeruleus nucleus, A5 cell group, Barrington's nucleus and periaqueductal gray matter. In the diencephalon, PRV labeled neurons were marked mostly in the paraventricular nucleus and a few ones were in the lateral hypothalamic nucleus, posterior hypothalamic nucleus, ventromedial hypothalamic nucleus, arcuate nucleus, median eminence, perifornical nucleus, periventricular nucleus and suprachiasmatic nucleus. In cerebral cortex, PRV labeled neurons were marked mostly in the frontal cortex, 1,2 area, hind limb area, agranular insular cortex. Immunoreactive neurons to Corticotropin releasiing factor(CRF), Corticotropin releasiing factor-receptor(CRF-R), c-fos and serotonin were a part of labeled areas among the virus-labeled neurons of urinary bladder and Wijung($BL_{40}$). The commonly labeled areas were nucleus tractus solitarius, area postrema, reticular nucleus, raphe nuclei(obscurus, magnus and pallidus), locus coeruleus, A5 cell group, Barrington,s nucleus, arcuate nucleus, paraventricular nucleus, frontal cortex 1, 2 area, hind limb, and perirhinal(agranular insular) cortex. These results suggest that overlapped CNS locations are related with autonomic nuclei which regulate the functions of urinary bladder-relate organs and it was revealed by tracing PRV labeled neurons projecting urinary bladder and urinary bladder-related acupoints. These commonly labeled areas often overlap with the neurons connected with hormones and hormone receptors related to urination.

• The Korean Journal of Physiology and Pharmacology
• /
• v.19 no.3
• /
• pp.275-281
• /
• 2015

Orthostatic hypotension is most common in elderly people, and its prevalence increases with age. Attenuation of the vestibulo-sympathetic reflex (VSR) is commonly associated with orthostatic hypotension. In this study, we investigated the role of glutamate on the vestibulo-solitary projection of the VSR pathway to clarify the pathophysiology of orthostatic hypotension. Blood pressure and expression of both pERK and c-Fos protein were evaluated in the nucleus tractus solitarius (NTS) after microinjection of glutamate into the medial vestibular nucleus (MVN) in conscious rats with sodium nitroprusside (SNP)-induced hypotension that received baroreceptor unloading via sinoaortic denervation (SAD). SNP-induced hypotension increased the expression of both pERK and c-Fos protein in the NTS, which was abolished by pretreatment with glutamate receptor antagonists (MK801 or CNQX) in the MVN. Microinjection of glutamate receptor agonists (NMDA or AMPA) into the MVN increased the expression of both pERK and c-Fos protein in the NTS without causing changes in blood pressure. These results indicate that both NMDA and AMPA receptors play a significant role in the vestibulo-solitary projection of the VSR pathway for maintaining blood pressure, and that glutamatergic transmission in this projection might play a key role in the pathophysiology of orthostatic hypotension.

• The Korean Journal of Pharmacology
• /
• v.25 no.1
• /
• pp.1-11
• /
• 1989

In this study, it was aimed to investigate the role of serotonergic neurotransmission in nucleus tractus solitarius (NTS) for the central regulation of blood pressure and heart rate and its involvement in baroreceptor reflex activation in rats. A microinjection of 5-hydroxytryptamine (5-HT) into the NTS produced decreases in blood pressure and heart rate. Maximal decreases were $34.4{\pm}1.6$ mmHg and $41.7{\pm}10.2$ beats per min by 300 pmol of 5-HT. Microinjections of ${\alpha}-methylnor-adrenaline$ $({\alpha}-MNE)$ and clonidine manifested similar decreases in blood pressure and heart rate. The hypotensive and bradycardial effects of 5-HT were blocked by previous applications of 5-HT antagonists, ritanserin, methysergide and ketanserin into the NTS, respectively. By pretreatment with reserpine and 6-hydroxydopamine (6-OHDA, i.c.v.), both hypotensive and bradycardial effects of 5-HT were significantly attenuated. Pretreatment with 5, 7-dihydroxytryptamine (5,7-DHT, i.c.v.) enhanced the hypotensive and bradycardial effects of 5-HT. Similarly, following pretreatment with 6-OHDA, the effects of clonidine were increased. Pretreatment either with 5,7-DHT or 6-OHDA significantly attenuated the sensitivity of baroreflex produced either by phenylephrine or by sodium nitroprusside. When either 5,7-DHT or 6-OHDA was injected into the NTS $(5,7-DHT;\;8{\mu}g\;6-OHDA;\;10{\mu}g)$, both of the baroreflex sensitivities were impaired. In the immunohistochemical study, the injection of 6-OHDA into the the NTS led to reduction of axon terminal varicosity, however, the injection did not reduce the numbers of catecholaminergic cell bodies. Likewise, when 5,7-DHT was injected into the NTS, the varicosity of serotonergic axon terminals was markedly reduced. Based on these results, it is suggested that (1) stimulation of serotonergic receptors in the NTS leads to decreases in blood pressure and heart rate as observed with the stimulation of catecholaminergic system, (2) both serotonergic and catecholaminergic receptors may be located postsynaptically, and (3) the serotonergic neurons as well as catecholaminergic neurons may have a close relevance for the activation of baroreflex.