• The Korean Journal of Physiology and Pharmacology
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• v.2 no.4
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• pp.521-527
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• 1998

An important property of the intestine is the ability to secrete fluid. The intestinal secretion is regulated by a number of substances including vasoactive intestinal peptide (VIP), ATP and different inflammatory mediators. One of the most important secretagogues is adenosine during inflammation. However, the controversy concerning the underlying mechanism of adenosine-stimulated $Cl^-$ secretion in intestinal epithelial cells still continues. To investigate the effect of adenosine on $Cl^-$ secretion and its underlying mechanism in the rabbit colon mucosa, we measured short circuit current ($I_{SC}$) under automatic voltage clamp with DVC-1000 in a modified Ussing chamber. Adenosine, when added to the basolateral side of the muocsa, increased $I_{SC}$ in a dose-dependent manner. The adenosine-stimulated $I_{SC}$ response was abolished when $Cl^-$ in the bath solution was replaced completely with gluconate. In addition, the $I_{SC}$ response was inhibited by a basolateral Na-K-Cl cotransporter blocker, bumetanide, and by apical $Cl^-$ channel blockers, dephenylamine-2-carboxylate (DPC), 5-nitro-2-(3-phenyl-propylamino)-benzoate (NPPB), glibenclamide. Amiloride, an epithelial $Na^+$ channel blocker, and 4,4-diisothiocyanato-stilbene-2,2-disulphonate (DIDS), a $Ca^{2+}-activated$ $Cl^-$ channel blocker, had no effect. In the mucosa pre-stimulated with forskolin, adenosine did not show any additive effect, whereas carbachol resulted in a synergistic potentiation of the $I_{SC}$ response. The adenosine response was inhibited by 10 ${\mu}M$ H-89, an inhibitor of protein kinase A. These results suggest that the adenosine-stimulated $I_{SC}$ response is mediated by basolateral to apical $Cl^-$ secretion through a cAMP-dependent $Cl^-$ channel. The rank order of potencies of adenosine receptor agonists was $5'-(N-ethylcarboxamino)adenosine(NECA)＞N^6-(R-phenylisopropyl)adenosine(R-$ PIA)＞2-[p-(2-carbonylethyl)-phenyl-ethylamino]-5'-N-ethylcarboxaminoadenosine(CGS21680). From the above results, it can be concluded that adenosine interacts with the $A_{2b}$ adenosine receptor in the rabbit colon mucosa and a cAMP-dependent signalling mechanism underlies the stimulation of $Cl^-$ secretion.

• Journal of Photoscience
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• v.9 no.2
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• pp.5-8
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• 2002

Photoperiodism is an important adaptive phenomenon in various physiological parameters including reproduction to cope with seasonal changes. Involvement of extraretinal photoreceptors in the photoperiodism in non-mammalian vertebrates has been well established. In addition, circadian clock system is known to be involved in the photoperiodic time measurement. The pathway consists of light-input system, time measurement system (circadian clock), gonadotropin releasing hormone (GnRH) production in the hypothalamus, luteinizing hormone (LH) and follicle stimulating hormone (FSH) production in the pituitary, and final gonadal development. Recently, several laboratories reported photopigments newly cloned in the pineal, eyes and deep brain in addition to already known visual pigments in the retina. These are pinopsin, parapinopsin, VA-opsin, melanopsin, etc. All these photopigments belong to the opsin family having retinal as the chromophore. However, the function of these photopigments remains unknown. I reviewed the studies on the location of the photopigments by immunocytochemistry. I also discussed the results on the action spectra for induction of gonadal development in relation with the location of the photoreceptors. Various physiologically active substances distribute in the vertebrate brain. Such substances are GnRH, GnIH, neuropeptide Y, vasoactive intestinal peptide, c-Fos, galanin, neurosteroids, etc. I summarized the immunhistochemical studies on the distribution and the photoperiodic changes of these substances and discussed the route from the deep brain photoreceptor to GnRH cells.

• The Journal of Dong Guk Oriental Medicine
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• v.8 no.1
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• pp.117-131
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• 1999

Yangkyuksanhoa-tang is frequently used for cerebrovascular accident(CVA). The present study was performed to investigate the effect of Yangkyuksanhoa-tang on the peri vascular immunoreactive nerve fiber of the basilar artery after experimentally induced subarachnoid hemorrhage(SAH). Sprague Dawley rats weighing between 350-400g were used. The SAH induced by injection of the fresh autologus heart blood(0.3-0.4ml) into the cisterna magna through the posterior atlanto-occipital membrane. Sample group was given a $3.3m{\ell}/kg/day$ of Yangkyuksanhoa-tang extracts for 2 days after SAH. The experimental animals divided into 48hrs after SAH. The changes of perivascular immunoreactive nerve fiber was examined by using indirect immunofluorescence method. The meshlike perivascular nerve fiber appeared in the basilar artery of normal rats. In basilar artery of SAH elicitated rat, the distribution of calcitonin gene-related peptide (CGRP)-immunoreactivity(IR) and vasoactive intestinal polypeptide(VIP)-IR of the perivascular nerve fiber were remarkably diminished, also dopamine beta hydroxylase(DBH)-IR, neuropeptide Y(NPY)-IR and serotonin-IR were diminished. In SAH elicitated rat with Yangkyuksanhoa-tang treatment, the CGRP-IR and VIP-IR degree were repaired as well as normal rat's, but DBH-IR, NPY-IR and serotonin-IR had no changes. These results provide the basic data to investigate the effect of Yangkyuksanhoa-tang on the vasospasm after SAH.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.6
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• pp.783-796
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• 1997

The relaxation induced by stimulation of the inhibitory non-adrenergic, non-cholinergic (iNANC) nerve is mediated by the release of iNANC neurotransmitters such as nitric oxide (NO), vasoactive intestinal peptide (VIP) and adenosine triphosphate (ATP). The mechanisms of NO, VIP or ATP-induced relaxation have been partly determined in previous studies, but the detailed mechanism remains unknown. We tried to identify the nature of iNANC neurotransmitters in the smooth muscle of guinea pig ileum and to determine the mechanism of the inhibitory effect of nitric oxide. We measured the effect of NO-donors VIP and ATP on the intracellular $Ca^{2+}$ concentration$([Ca^{2+}]_i)$, by means of a fluorescence dye(fura 2) and tension simultaneously in the isolated guinea pig ileal smooth muscle. Following are the results obtained. 1. Sodium nitroprusside $(SNP:10^{-5}\;M)$ or S -nitro-N-acetyl-penicillamine $(SNP:10^{-5}\;M)$ decreased resting $[Ca^{2+}]_i$ I and tension of muscle. SNP or SNAP also inhibited rhythmic oscillation of $[Ca^{2+}]_i$ and tension. In 40mM $K^+$ solution or carbachol ($(CCh:10^{-6}\;M)$-induced precontracted muscle, SNP decreased muscle tension. VIP did not change $[Ca^{2+}]_i$ and tension in the resting or precontracted muscle, but ATP increased resting $[Ca^{2+}]_i$ and tension in the resting muscle. 2. 1H-[1,2,4]oxadiazol(4,3-a)quinoxalin-1-one $(ODQ:1\;{\mu}M)$, a specific inhibitor of soluble guanylate cyclase, limited the inhibitory effect of SNP 3. Glibenclamide $(10\;{\mu}M)$, a blocker of $K_{ATP}$ channel, and 4-aminopyridine (4-AP:5 mM), a blocker of delayed rectifier K channel, apamin $(0.1\;{\mu}M)$, a blocker of small conductance $K_{Ca}$ channel had no effect on the inhibitory effect of SNP. Iberiotoxin $(0.1\;{\mu}M)$, a blocker of large conductance $K_{Ca}$ channel, significantly increased the resting $[Ca^{2+}]_i$, and tension, and limited the inhibitory effect of SNP. 4. Nifedipine $(1\;{\mu}M)$ or elimination of external $Ca^{2+}$ decreased not only resting $[Ca^{2+}]_i$ and tension but also oscillation of $[Ca^{2+}]_i$ and tension. Ryanodine $(5\;{\mu}M)$ and cyclopiazonic acid $(10\;{\mu}M)$ decreased oscillation of $[Ca^{2+}]_i$ and tension. 5. SNP decreased $Ca^{2+}$ sensitivity of contractile protein. In conclusion, these results suggest that 1) NO is an inhibitory neurotransmitter in the guinea pig ileum, 2) the inhibitory effect of SNP on the $[Ca^{2+}]_i$ and tension of the muscle is due to a decrease in $[Ca^{2+}]_i$ by activation of the large conductance $K_{Ca}$ channel and a decrease in the sensitivity of contractile elements to $Ca^{2+}$ through activation of G-kinase.

• Journal of Chest Surgery
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• v.29 no.5
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• pp.487-494
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• 1996

The neurogenic responses of tracheal smooth muscles to electrical field stimulation (EFS) is biphasic, consisting firstly of cholinergic contraction followed by a slow and sustained relaxation. It is well known that a sustained relaxation involves the inhibitory non-adrenergic non-cholinergic systems. This study was done to Investigate the relaxing agents and their action mechanisms by use of an organ bath with plati- ilum . The tracheal smooth muscle relaxation due to EFS was suppressed by L-NAME, the WO (Nitric Oxide) synthase inhibitor, and these effects were reversed by L-arginine, the precursor of NO. Also, L-WAME (HG-nitro-L-arginine methyl ester) increased the basal tension. Nitroprusside, the NO-donor, suppressed the tracheal basal tension greatly. Methylene blue, the inhibitor of guanylate cyclase, decreased EFS-induced relaxations and increa ed basal tension. Forskolin and isoprenaline, which are activators of adenylate cyclase, suppressed tracheal basal tension in the same way as nitroprusside. TEA (tetraethylammonium), the non-specific K'channel blocker, and apamin, the Ca"-activated K'channel blocker, increased tracheal basal tension and EFS-induced relaxations. Our results indicate that Pr3 Is released upon stimulation of the NANC (Won Adrenergic Won Cholinergic) nerves in guinea-pig tracheal smooth muscle and that the release of NO related with the K+ channel, as well as the release of other inhibitory agents< e. g.)VIP (Vasoactive Intestinal Polypeptide), PHI (Peptide Histidine Isoleusine) > mediated via CAMP (cyclic Adenosine Monophosphate) may be Involved In sustained relaxation.

• Korean Journal of Veterinary Research
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• v.40 no.2
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• pp.197-211
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• 2000

The pineal body have been known to be affected by superior cervical ganglia, and most of its nerve fibers containing peptidergic neurotransmitters have been considered to be originated from this ganglia. To confirm this relationships, some peptidergic neurotransmitters were identified in both of pineal body and superior cervical ganglia of the Korean native goat, which were divided into two group; breeding season and non-breeding season. The localizations of two catecholamine-synthesizing enzymes; tyrosine hydroxylase (TH) and dopamine beta-hydroxylase (DBH), were investigated by immunohistochemistry in the superior cervical ganglia and the pineal body of adult Korean native goats. Substance P (SP), calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY) and galanin (GAL) were also identified in these organs by immunohistochemical and double immunofluorescent methods. In superior cervical ganglia, immunoreactivities for TH and DBH were confirmed in the same ganglion cells. The immunoreactivites for SP, VIP(only in male), NPY and GAL were identified in both of ganglion cell bodies and nerve fibers in the ganglia. CGRP immunoreactivity, however, was observed only in nerve fibers. Most NPY- and VIP-immunoreactive(IR) ganglion cells also contained TH. SP and TH were colocalized in the cell bodies, but not in the nerve fibers. TH immunoreactivity was shown in almost all of ganglion cells in the superior cervical ganglia. The immunoreactivity for NPY had some seasonal variation and was stronger in breeding season than in non-breeding season. In pineal body, lots of TH-IR fibers were observed throughout the parenchyma including the pineal stalk and most of them also contained DBH. SP- and NPY-IR fibers were also immunostained with TH or DBH. But a few SP- and NPY-IR fibers were not colocalized with TH or DBH. Exceptionally, a bipolar neuron-like cell was observed to be immunostained with NPY in the pineal body. A few CGRP and GAL-IR fibers were observed, while VIP-IR fibers were not present. It is concluded that most TH- and DBH-IR fibers as well as the peptidergic immunoreactive fibers of the pineal body might be originated from the superior cervical ganglia. Some peptidergic immunoreactive fibers, however, might be come from other regions of brain. We also suggest that NPY in pineal body plays a important role for pineal function. The seasonal variation of NPY immunoreactivity indicates that the synthesis and use of NPY may be different between in breeding and non-breeding seasons.