Effects of Arachidonic Acid on the Calcium Channel Current (<I>I</I><SUB>Ba</SUB>) and on the Osmotic Stretch-induced Increase of <I>I</I><SUB>Ba</SUB> in Guinea-Pig Gastric Myocytes

Wen Xie Xu,Sung Joon Kim,Insuk So,Suk Hyo Suh,Ki Whan Kim 대한생리학회-대한약리학회 1997 The Korean Journal of Physiology & Pharmacology Vol.1 No.4

<P> We employed the whole-cell patch clamp technique to investigate the effects of arachidonic acid (AA) on barium inward current through the L-type calcium channels (<I>I</I><SUB>Ba</SUB>) and on osmotic stretch-induced increase of <I>I</I><SUB>Ba</SUB> in guinea-pig antral gastric myocytes. Under isosmotic condition, AA inhibited <I>I</I><SUB>Ba</SUB> in a dose-dependent manner to 91.1⁑1.4, 72.0⁑3.2, 46.0⁑1.8, and 20.3⁑2.3% at 1, 5, 10, 30 mM, respectively. The inhibitory effect of AA was not affected by 10 ㄍM indomethacin, a cyclooxygenase inhibitor. Other unsaturated fatty acids, linoleic acid (LA) and oleic acid (OA) were also found to suppress <I>I</I><SUB>Ba</SUB> but stearic acid (SA), a saturated fatty acid, had no inhibitory effect on <I>I</I><SUB>Ba</SUB>. The potency sequence of these inhibitory effects was AA (79.7⁑2.3%) > LA (43.1⁑2.7%) > OA (14.2⁑1.1%) at 30 ㄍM. On superfusing the myocyte with hyposmotic solution (214 mOsm) the amplitude of <I>I</I><SUB>Ba</SUB> at 0 mV increased (38.0⁑5.5%); this increase was completely blocked by pretreatment with 30 mM AA, but not significantly inhibited by lower concentrations of AA (1, 5 and 10 ㄍM) (P>0.05). Unsaturated fatty acids shifted the steady-state inactivation curves of <I>I</I><SUB>Ba</SUB> to the left; the extent of shift caused by AA was greater than that caused by LA. The activation curve was not affected by AA or LA. The results suggest that AA and other unsaturated fatty acids directly modulate L-type calcium channels and AA might modulate the hyposmotic stretch- induced increase of L-type calcium channel current in guinea-pig gastric smooth muscle.

Changes of Cytosolic Ca<SUP>2⁢</SUP> under Metabolic Inhibition in Isolated Rat Ventricular Myocytes

Sunghyun Kang,Nari Kim,Hyun Joo,Jae Boum Youm,Won Sun Park,Mohamed Warda,Hyungkyu Kim,Dang Van Cuong,Taeho Kim,Euiyong Kim,Jin Han 대한생리학회-대한약리학회 2005 The Korean Journal of Physiology & Pharmacology Vol.9 No.5

To characterize cytosolic Ca<SUP>2⁢</SUP> fluctuations under metabolic inhibition, rat ventricular myocytes were exposed to 200μM 2,4-dinitrophenol (DNP), and mitochondrial Ca<SUP>2⁢</SUP>, mitochondrial membrane potential (ΔΨ<SUB>m</SUB>), and cytosolic Ca<SUP>2⁢</SUP> were measured, using Rhod-2 AM, TMRE, and Fluo-4 AM fluorescent dyes, respectively, by Laser Scanning Confocal Microscopy (LSCM). Furthermore, the role of sarcolemmal Na<SUP>⁢</SUP>/Ca<SUP>2⁢</SUP> exchange (NCX) in cytosolic Ca<SUP>2⁢</SUP> efflux was studied in KB-R7943 and Na<SUP>⁢</SUP>-free normal Tyrode s solution (143 mM LiCl ). When DNP was applied to cells loaded with Fluo-4 AM, Fluo-4 AM fluorescence intensity initially increased by 70⁑10% within 70⁑10 s, and later by 400⁑200% at 850⁑46 s. Fluorescence intensity of both Rhod-2 AM and TMRE were initially decreased by DNP, coincident with the initial increase of Fluo-4 AM fluorescence intensity. When sarcoplasmic reticulum (SR) Ca<SUP>2⁢</SUP> was depleted by 1μM thapsigargin plus 10μM ryanodine, the initial increase of Fluo-4 AM fluorescence intensity was unaffected, however, the subsequent progressive increase was abolished. KB-R7943 delayed both the first and the second phases of cytosolic Ca<SUP>2⁢</SUP> overload, while Na<SUP>⁢</SUP>-free solution accelerated the second. The above results suggest that: 1) the initial rise in cytosolic Ca<SUP>2⁢</SUP> under DNP results from mitochondrial depolarization; 2) the secondary increase is caused by progressive Ca<SUP>2⁢</SUP> release from SR; 3) NCX plays an important role in transient cytosolic Ca<SUP>2⁢</SUP> shifts under metabolic inhibition with DNP.

Polyphenols of Rubus coreanum Inhibit Catecholamine Secretion from the Perfused Adrenal Medulla of SHRs

Byung-Sik Yu,Duck-Mi Na,Mi-Young Kang,Dong-Yoon Lim 대한생리학회-대한약리학회 2009 The Korean Journal of Physiology & Pharmacology Vol.13 No.6

The present study was attempted to investigate whether polyphenolic compounds isolated from wine, which is brewed from Rubus coreanum Miquel (PCRC), may affect the release of catecholamines (CA) from the isolated perfused adrenal medulla of the spontaneously hypertensive rats (SHRs), and to establish its mechanism of action. PCRC (20∼180Ռg/ml) perfused into an adrenal vein for 90 min relatively dose-dependently inhibited the CA secretory responses to ACh (5.32 mM), high K⁺ (56 mM), DMPP (100ՌM) and McN-A-343 (100ՌM). PCRC itself did not affect basal CA secretion (data not shown). Also, in the presence of PCRC (60Ռg/ml), the CA secretory responses to veratridine (a selective Na⁺ channel activator (10ՌM), Bay-K-8644 (a L-type dihydropyridine Ca²⁺ channel activator, 10ՌM), and cyclopiazonic acid (a cytoplasmic Ca²⁺-ATPase inhibitor, 10ՌM) were significantly reduced, respectively. In the simultaneous presence of PCRC (60Ռg/ml) and L-NAME (an inhibitor of NO synthase, 30ՌM), the inhibitory responses of PCRC on the CA secretion evoked by ACh, high K⁺, DMPP, and Bay-K-8644 were considerably recovered to the extent of the corresponding control secretion compared with that of PCRC-treatment alone. The level of NO released from adrenal medulla after the treatment of PCRC (60Ռg/ml) was greatly elevated compared with the corresponding basal level. Taken together, these results demonstrate that PCRC inhibits the CA secretion from the isolated perfused adrenal medulla of the SHRs evoked by stimulation of cholinergic receptors as well as by direct membrane-depolarization. It seems that this inhibitory effect of PCRC is mediated by blocking the influx of calcium and sodium into the adrenal medullary chromaffin cells of the SHRs as well as by inhibition of Ca²⁺ release from the cytoplasmic calcium store at least partly through the increased NO production due to the activation of NO synthase.

Sorting Nexin 17 Interacts Directly with Kinesin Superfamily KIF1B<FONT FACE= HCI Tulip >Ղ Protein

Dae-Hyun Seog,Jin Han 대한생리학회-대한약리학회 2008 The Korean Journal of Physiology & Pharmacology Vol.12 No.4

KIF1BՂ is a member of the Kinesin superfamily proteins (KIFs), which are microtubule-dependent molecular motors that are involved in various intracellular organellar transport processes. KIF1BՂ is not restricted to neuronal systems, however, is widely expressed in other tissues, even though the function of KIF1BՂ is still unclear. To elucidate the KIF1BՂ-binding proteins in non-neuronal cells, we used the yeast two-hybrid system, and found a specific interaction of KIF1BՂ and the sorting nexin (SNX) 17. The C-terminal region of SNX17 is required for the binding with KIF1BՂ. SNX17 protein bound to the specific region of KIF1BՂ (813-916. aa), but not to other kinesin family members. In addition, this specific interaction was also observed in the Glutathione S-transferase pull-down assay. An antibody to SNX17 specifically co-immunoprecipitated KIF1BՂ associated with SNX17 from mouse brain extracts. These results suggest that SNX17 might be involved in the KIF1BՂ-mediated transport as a KIF1BՂ adaptor protein.

Resveratrol Inhibits Nicotinic Stimulation-Evoked Catecholamine Release from the Adrenal Medulla

Seong-Chang Woo,Gwang-Moon Na,Dong-Yoon Lim 대한생리학회-대한약리학회 2008 The Korean Journal of Physiology & Pharmacology Vol.12 No.4

Resveratrol has been known to possess various potent cardiovascular effects in animal, but there is little information on its functional effect on the secretion of catecholamines (CA) from the perfused model of the adrenal medulla. Therefore, the aim of the present study was to determine the effect of resveratrol on the CA secretion from the isolated perfused model of the normotensive rat adrenal gland, and to elucidate its mechanism of action. Resveratrol (10∼100ՌM) during perfusion into an adrenal vein for 90 min inhibited the CA secretory responses evoked by ACh (5.32 mM), high K⁺ (a direct membrane-depolarizer, 56 mM), DMPP (a selective neuronal nicotinic N_n receptor agonist, 100ՌM) and McN-A-343 (a selective muscarinic M₁ receptor agonist, 100ՌM) in both a time- and dose- dependent fashion. Also, in the presence of resveratrol (30ՌM), the secretory responses of CA evoked by veratridine 8644 (an activator of voltage-dependent Na⁺ channels, 100ՌM), Bay-K-8644 (a L-type dihydropyridine Ca²⁺ channel activator, 10ՌM), and cyclopiazonic acid (a cytoplasmic Ca²⁺-ATPase inhibitor, 10ՌM) were significantly reduced. In the simultaneous presence of resveratrol (30ՌM) and L-NAME (an inhibitor of NO synthase, 30ՌM), the CA secretory evoked by ACh, high K⁺, DMPP, McN-A-343, Bay-K-8644 and cyclopiazonic acid were recovered to a considerable extent of the corres</SUP>ponding control secretion compared with the inhibitory effect of resveratrol alone. Interestingly, the amount of nitric oxide (NO) released from the adrenal medulla was greatly increased in comparison to its basal release. Taken together, these experimental results demonstrate that resveratrol can inhibit the CA secretory responses evoked by stimulation of cholinergic nicotinic receptors, as well as by direct membrane-depolarization in the isolated perfused model of the rat adrenal gland. It seems that this inhibitory effect of resveratrol is exerted by inhibiting an influx of both ions through Na⁺ and Ca²⁺ channels into the adrenomedullary cells as well as by blocking the release of Ca²⁺ from the cytoplasmic calcium store, which are mediated at least partly by the increased NO production due to the activation of NO synthase.

Kinesin Superfamily KIF5 Proteins Bind to βIII Spectrin

Jae-Eun Paik,Nari Kim,Sung Su Yea,Won Hee Jang,Joon-Young Chung,Sang-Kyoung Lee,Yeong-Hong Park,Jin Han,Dae-Hyun Seog 대한생리학회-대한약리학회 2004 The Korean Journal of Physiology & Pharmacology Vol.13 No.1

The kinesin proteins (KIFs) make up a large superfamily of molecular motors that transport cargo such as vesicles, protein complexes, and organelles. KIF5 is a heterotetrameric motor that conveys vesicles and plays an important role in neuronal function. Here, we used the yeast two-hybrid system to identify the neuronal protein(s) that interacts with the tail region of KIF5 and found a specific interaction with βIII spectrin. The amino acid residues between 1394 and 1774 of βIII spectrin were required for the interaction with KIF5C. βIII spectrin also bound to the tail region of neuronal KIF5A and ubiquitous KIF5B but not to other kinesin family members in the yeast two-hybrid assay. In addition, these proteins showed specific interactions, confirmed by GST pull-down assay and co-immunoprecipitation. βIII spectrin interacted with GST-KIF5 fusion proteins, but not with GST alone. An antibody to βIII spectrin specifically co-immunoprecipitated KIF5s associated with βIII spectrin from mouse brain extracts. These results suggest that KIF5 motor proteins transport vesicles or organelles that are coated with βIII spectrin.

p66shc Adaptor Protein Suppresses the Activation of Endothelial Nitric Oxide Synthase in Mouse Embryonic Fibroblasts

Sang Ki Lee,Young Shin Kim,Cuk Seong Kim,Sook Jin Son,Dae Goon Yoo,Kwon Ho Lee,Sang Do Lee,Jin Bong Park,Byeong Hwa Jeon 대한생리학회-대한약리학회 2006 The Korean Journal of Physiology & Pharmacology Vol.10 No.3

Among the Shc proteins, p66shc is known to be related to oxidative stress responses and regulation of the production of reactive oxygen species (ROS). The present study was undertaken to investigate the role of p66shc on endothelial nitric oxide synthase (eNOS) activity in the mouse embryonic fibroblasts (MEFs). When wild type (WT) or p66shc (⁣/⁣) MEFs were transfected with full length of eNOS cDNA, the expression and activity of eNOS protein were higher in the p66shc (⁣/⁣) MEFs. These phenomena were reversed by reconstitution of p66shc cDNA transfection in the p66shc (⁣/⁣) MEFs. The basal superoxide production in the p66shc (⁣/⁣) MEFs was not significantly different from that of WT of MEFs. However, superoxide production induced by NADPH in the p66shc (⁣/⁣) MEF was lesser than that in WT MEFs. When compared with WT MEFs, cell lysate of p66shc (⁣/⁣) MEFs showed significantly increased H-ras activity without change of endogenous H-ras expression. Our findings suggest the pivotal role of p66shc adaptor protein played in inhibition of endothelial nitric oxide production via modulation of the expression and/or activity of eNOS protein.

Effects of Phosphodiesterase 5 Inhibition with Sildenafil on Atrial Contractile and Secretory Function

He Xiu Quan,Sun Young Kim,Xuan Shun Jin,Jong Kwan Park,Sung Zoo Kim,Kyung Woo Cho 대한생리학회-대한약리학회 2006 The Korean Journal of Physiology & Pharmacology Vol.10 No.3

Selective inhibition of phosphodiesterase (PDE) 5 opened a new therapeutic approach for cardiovascular disorders. Therefore, the effect of PDE5 inhibition on the cardiac function should thoroughly be defined. The purpose of the present study was to define the effects of sildenafil, a selective inhibitor of PDE5, on the atrial cGMP efflux, atrial dynamics, and the release of atrial natriuretic peptide (ANP). By perfusing rabbit left atria to allow atrial pacing, changes in atrial stroke volume and pulse pressure, transmural extracellular fluid translocation, cGMP efflux, and ANP secretion were measured. SIN-1, an NO donor and soluble (s) guanylyl cyclase (GC) activator, and C-type natriuretic peptide (CNP), an activator of particulate (p) GC activator, were used. Sildenafil increased basal levels of cGMP efflux slightly but not significantly. Sildenafil in a therapeutic dose increased atrial dynamics (for atrial stroke volume, 2.84⁑1.71%, n=12, vs ⁣0.71⁑0.86%, n=21; p<0.05) and decreased ANP release (⁣9.02⁑3.36%, n=14, vs 1.35⁑3.25%, n=23; p<0.05), however, it had no effect on the SIN-1- or CNP-induced increase of cGMP levels. Furthermore, sildenafil in a therapeutic dose accentuated SIN-1-induced, but not CNP- induced, decrease of atrial pulse pressure and ANP release. These data indicate that PDE5 inhibition with sildenafil has a minor effect on cGMP levels, but has a distinct effect on pGC-cGMP- and sGC- cGMP-induced contractile and secretory function.

Carthamus tinctorius L. Increases BMP-2 Gene Expression during Bone Fracture Healing in Rats

Kwang-Hee Lee,Oog-Jin Sohn,Jong-Chul Ahn,Yong-Woon Kim,So-Young Park,Jong-Yeon Kim 대한생리학회-대한약리학회 2006 The Korean Journal of Physiology & Pharmacology Vol.10 No.3

Carthamus tinctorius L.is known to improve fracture healing, and bone morphogenetic proteins (BMPs) are associated with the formation and healing process of bone. BMP-2 and BMP-7 are two of the most important BMPs during the bone healing process. Human osteosarcoma MG63 cells and rats were used to determine the effects of Carthamus tinctorius L. extract (CTE) on BMP-2 gene expression. BMP-2 gene expression by CTE treatment in human osteosarcoma MG63 cells was not different from the control group until 8 hours of incubation, but was significantly higher, by 31%, than that of the control group at 16 hr of incubation. Microscopic findings of the 9th rib 3 weeks after fracture showed typical rimming of the osteoblast and immature bone formation in control and CTE groups. BMP-2 gene expression by in situ hybridization was remarkably increased by a CTE-supplemented diet in the fracture group compared to the control group. In conclusion, Carthamus tinctorius L. increased BMP-2 gene expression in human osteosarcoma cells and fractured bone. But further studies would be needed to elucidate the effect of CTE on fracture healing in vivo because our results did not show any evidence of healing improvement histologically 3<SUP>rd</SUP> week after fracture.

Gintonin facilitates catecholamine secretion from the perfused adrenal medulla

Seung-Yeol Na,Ki-Hwan Kim,Mi-Sung Choi,Kang-Su Ha,Dong-Yoon Lim 대한생리학회-대한약리학회 2016 The Korean Journal of Physiology & Pharmacology Vol.20 No.6

The present study was designed to investigate the characteristics of gintonin, one of components isolated from Korean Ginseng on secretion of catecholamines (CA) from the isolated perfused model of rat adrenal gland and to clarify its mechanism of action. Gintonin (1 to 30 μg/ml), perfused into an adrenal vein, markedly increased the CA secretion from the perfused rat adrenal medulla in a dose-dependent fashion. The gintonin-evoked CA secretion was greatly inhibited in the presence of chlorisondamine (1 μM, an autonomic ganglionic bloker), pirenzepine (2 μM, a muscarinic M₁ receptor antagonist), Ki14625 (10 μM, an LPA_1/3 receptor antagonist), amiloride (1 mM, an inhibitor of Na⁺/Ca²⁺ exchanger), a nicardipine (1 μM, a voltage-dependent Ca²⁺ channel blocker), TMB-8 (1 μM, an intracellular Ca²⁺antagonist), and perfusion of Ca²⁺-free Krebs solution with 5mM EGTA (a Ca²⁺chelater), while was not affected by sodium nitroprusside (100 μM, a nitrosovasodialtor). Interestingly, LPA (0.3~3 μM, an LPA receptor agonist) also dose-dependently enhanced the CA secretion from the adrenal medulla, but this facilitatory effect of LPA was greatly inhibited in the presence of Ki 14625 (10 μM). Moreover, acetylcholine (AC)-evoked CA secretion was greatly potentiated during the perfusion of gintonin (3 μg/ml). Taken together, these results demonstrate the first evidence that gintonin increases the CA secretion from the perfused rat adrenal medulla in a dose-dependent fashion. This facilitatory effect of gintonin seems to be associated with activation of LPA- and cholinergic-receptors, which are relevant to the cytoplasmic Ca²⁺ increase by stimulation of the Ca²⁺ influx as well as by the inhibition of Ca²⁺ uptake into the cytoplasmic Ca²⁺ stores, without the increased nitric oxide (NO). Based on these results, it is thought that gintonin, one of ginseng components, can elevate the CA secretion from adrenal medulla by regulating the Ca²⁺ mobilization for exocytosis, suggesting facilitation of cardiovascular system. Also, these findings show that gintonin might be at least one of ginseng-induced hypertensive components.