Responses of Dorsal Horn Neurons to Peripheral Chemical Stimulation in the Spinal Cord of Anesthetized Cats

Sung Jun Jung,Joo Min Park,Joon Ho Lee,Ji Hye Lee,Su-Yong Eun,Sang Jeong Kim,Won-Il Lim,Sun Hee Cho,Jun Kim 대한생리학회-대한약리학회 2000 The Korean Journal of Physiology & Pharmacology Vol.4 No.1

<P> Although nociceptive informations are thought to be processed via different neural mechanisms depending on the types of stimuli, sufficient data have not been accumulated yet. We performed a series of experiments to elucidate the possible neural mechanisms as to chemical stimuli such as formalin, capsaicin and ATP. <P>Single unit activity of wide dynamic range (WDR) neurons and high threshold cells were recorded extracellularly from the lumbosacral enlargement of cat spinal cord before and after chemical stimulation to its receptive field (RF). Each chemical substance - formalin (20μl, 4%), capsaicin (33 mM) or Mg-ATP (5 mM)- was injected intradermally into the RFs and then the changes in the spontaneous activity, mechanical threshold and responses to the peripheral mechanical stimuli were observed. In many cases, intradermal injection of formalin (5/11) and capsaicin (8/11) resulted in increase of the spontaneous activity with a biphasic pattern, whereas ATP (8/8) only showed initial responses. Time courses of the biphasic pattern, especially the late response, differed between formalin and capsaicin experiments. One hour after injection of each chemical (formalin, capsaicin, or ATP), the responses of the dorsal horn neurons to mechanical stimuli increased at large and the RFs were expended, suggesting development of hypersensitization (formalin 6/10, capsaicin 8/11, and ATP 15/19, respectively). These results are suggested that formalin stimulates peripheral nociceptor, local inflammation and involvement of central sensitization, capsaicin induces central sensitization as well as affects the peripheral C-polymodal nociceptors and neurogenic inflammation, and ATP directly stimulates peripheral nociceptors.

Protective Effects of Oleic Acid Against Palmitic Acid-Induced Apoptosis in Pancreatic AR42J Cells and Its Mechanisms

Joung Hoon Ahn,Min Hye Kim,Hyung Joo Kwon,Soo Young Choi,Hyeok Yil Kwon 대한생리학회-대한약리학회 2013 The Korean Journal of Physiology & Pharmacology Vol.17 No.1

Palmitic acid (PAM), one of the most common saturated fatty acid (SFA) in animals and plants, has been shown to induce apoptosis in exocrine pancreatic AR42J cells. In this study, we investigated cellular mechanisms underlying protective effects of oleic acid (OLA) against the lipotoxic actions of PAM in AR42J cells. Exposure of cells to long-chain SFA induced apoptotic cell death determined by MTT cell viability assay and Hoechst staining. Co-treatment of OLA with PAM markedly protected cells against PAM-induced apoptosis. OLA significantly attenuated the PAM-induced increase in the levels of pro-apoptotic Bak protein, cleaved forms of apoptotic proteins (caspase-3, PARP). On the contrary, OLA restored the decreased levels of anti-apoptotic Bcl-2 family proteins (Bcl-2, Bcl-xL, and Mcl-1) in PAM-treated cells. OLA also induced up-regulation of the mRNA expression of Dgat2 and Cpt1 genes which are involved in triacylglycerol (TAG) synthesis and mitochondrial Ղ-oxidation, respectively. Intracellular TAG accumulation was increased by OLA supplementation in accordance with enhanced expression of Dgat2 gene. These results indicate that restoration of anti-apoptotic/pro-apoptotic protein balance from apoptosis toward cell survival is involved in the cytoprotective effects of OLA against PAM-induced apoptosis in pancreatic AR42J cells. In addition, OLA-induced increase in TAG accumulation and up-regulation of Dgat2 and Cpt1 gene expressions may be possibly associated in part with the ability of OLA to protect cells from deleterious actions of PAM.

Alteration of Substrate Specificity by Common Variants, E158K/E308G and V257M, in Human Hepatic Drug-metabolizing Enzyme, Flavin-containing Monooxygenase 3

Jung-Kyu Lee,Ju-Hee Kang,Young-Nam Cha,Woon-Gye Chung,Chang-Shin Park 대한생리학회-대한약리학회 2003 The Korean Journal of Physiology & Pharmacology Vol.5 No.1

Our earlier studies found a significant correlation between the activities of ranitidine <I>N</I>-oxidation catalyzed by hepatic flavin-containing monooxygenase (FMO) and the presence of mutations in exon 4 (E158K) and exon 7 (E308G) of the <I>FMO3</I> gene in Korean volunteers. However, caffeine <I>N</I>-1 deme</I>thylation (which is also partially catalyzed by FMO) was not significantly correlated with these <I>FMO3</I> mutations. In this study, we examined another common mutation (V257M) in exon 6 of <I>FMO3 </I>gene. The V257M variant, which is caused by a point mutation (G769A), was commonly observed (13.21% allele frequency) in our subjects (n=159). This point mutation causes a substitution of Val<SUP>257</SUP> to Met<SUP>257</SUP>, with transformation of the secondary structure. The presence of this mutant allele correlated significantly with a reduction in caffeine <I>N-</I>1-demethylating activity, but was not correlated with the activity of <I>N</I>-oxidation of ranitidine. In a family study, the low FMO activity observed in a person heterozygous for a nonsense mutation in exon 4 (G148X) and heterozygous for missense mutation in exon 6 (V257M) of <I>FMO3 </I>was attributed to the mutations. Our results suggest that various point mutations in the coding regions of <I>FMO3</I> may influence FMO3 activity according to the probe substrates of varying chemical structure that correlate with each mutation on the <I>FMO3</I> gene.

N-Type Calcium Channels

Keith S. Elmslie 대한생리학회-대한약리학회 2000 The Korean Journal of Physiology & Pharmacology Vol.4 No.6

<P> The early studies of cardiac and smooth muscle cells provided evidence for two different calcium channels, the L-type (also called high-voltage activated [HVA]) and the T-type (low-voltage activated [LVA]). These calcium channels provided calcium for muscle contractions and pace-making activities. As might be expected, the number of different calcium channels increased when researchers studied neurons and the identification of the neuronal calcium channel has proven to be much more difficult than with the muscle calcium channels. There are two reasons for this difficulty; (1) a larger number of different calcium channels in neurons and (2) many of the different calcium channels have similar kinetic properties. This review uses the N-type calcium channel to illustrate the difficulties in identifying and characterizing calcium channels in neurons. It shows that the discovery of toxins that can specifically block single calcium channel types has made it possible to easily and rapidly discern the physiological roles of the different calcium channels in the neuron. Without these toxins it is unlikely that progress would have been as rapid.

Inhibition of Tumor Necrosis Factor-α mRNA Expression by a Limited Series of Tetrahydroisoquinolines in Mouse Peritoneal Macrophages

Tae Ho Jung,Young Soo Lee,Young Jin Kang,Bog Kyu Lee,Young Shin Ko,Han Geuk Seo,Soo Youn Chung,Duck-Hyung Lee,Hye Sook Yun-Choi,Ki Churl Chang 대한생리학회-대한약리학회 2000 The Korean Journal of Physiology & Pharmacology Vol.4 No.4

<P> Tumor necrosis factor-α (TNF-α) plays important roles in inflammatory responses. Some of tetrahydroisoquinoline (THI) compounds exhibited to inhibit iNOS expression in animal studies and RAW 264.7 cells, but the action of THI on inflammatory reaction was not fully investigated. In the present study, we examined a limited series of THIs (higenamine, YS-51 and THI-52) on the TNF-α mRNA expression in mouse peritoneal macrophages by Northern analysis. When thioglycollate-stimulated peritoneal macrophages were incubated with LPS (100 ng/ml), expression of TNF-α mRNA was evident and reached its maximum at 2.5 h, which was reduced concentration-dependently by treatment with THIs. When the TNF-α activity of macrophage-conditioned media was measured using a TNF-sensitive L929 fibroblast cell line, CCL 1, all THIs increased the cell viability in a concentration dependent manner. The concentrations of THIs used are not cytotoxic by itself when analysed by MTT. Furthermore, nitrite/nitrate level was significantly reduced by the presence of THIs in cells treated with LPS⁢interferon-γ (IFN-γ). It is concluded, thus, that these results strongly indicated that THIs can suppress the TNF-α expression and reduce NO, which may be useful for the inflammatory disorders.

Seasonal acclimation in sudomotor function evaluated by QSART in healthy humans

Young Oh Shin,Jeong-Beom Lee,Jeong-Ho Kim 대한생리학회-대한약리학회 2016 The Korean Journal of Physiology & Pharmacology Vol.20 No.5

The quantitative sudomotor axon reflex testing (QSART) is a classic test of routine postganglionic sudomotor function. We investigated sudomotor function by QSART after summer (July 2012) and winter (January 2013) seasonal acclimation (SA) in the Republic of Korea. QSART with acetylcholine (ACh) iontophoresis were performed to determine directly activated (DIR) and axon reflex-mediated (AXR1, 2) sweating rate. Onset time of axon reflex, activated sweat gland density (ASGD), activated sweat gland output (ASGO), tympanic and skin temperatures (T_ty, T_sk), basal metabolic rate (BMR), and evaporative loss volume changes were measured. Tympanic and mean body temperature (_Tb; calculated from T_ty, T_sk) were significantly lower after summer-SA than that of winter-SA. Sweat onset time was delayed during winter-SA compared to that after summer-SA. BMR, AXR(1), AXR(2), and DIR sweat rates, ASGD and ASGO, and evaporative loss volume were significantly diminishedafter winter-SA relative to after summer-SA. In conclusion, changes in sweating activity measured by QSART confirmed the involvement of the peripheral nervous system in variation of sudomotor activity in seasonal acclimation.

Decreased Voltage Dependent K<SUP>⁢</SUP> Currents in Cerebral Arterial Smooth Muscle Cells of One-Kidney, One-Clip Goldblatt Hypertensive Rat

Young Sun Oh,Se Hoon Kim,Hoe Suk Kim,Byeong Hwa Jeon,Seok Jong Chang,Kwang Jin Kim 대한생리학회-대한약리학회 1999 The Korean Journal of Physiology & Pharmacology Vol.3 No.5

<P> The Kv channel activity in vascular smooth muscle cell plays an important role in the regulation of membrane potential and blood vessel tone. It was postulated that increased blood vessel tone in hypertension was associated with alteration of Kv channel and membrane potential. Therefore, using whole cell mode of patch-clamp technique, the membrane potential and the 4-AP-sensitive Kv current in cerebral arterial smooth muscle cells were compared between normotensive rat and one-kidney, one-clip Goldblatt hypertensive rat (1K,1C-GBH rat). Cell capacitance of hypertensive rat was similar to that of normotensive rat. Cell capacitance of normotensive rat and 1K,1C-GBH rat were 20.8⁑2.3 and 19.5⁑1.4 pF, respectively. The resting membrane potentials measured in current clamp mode from normotensive rat and 1K,1C-GBH rat were ⁣45.9⁑1.7 and ⁣38.5⁑1.6 mV, respectively. 4-AP (5 mM) caused the resting membrane potential hypopolarize but charybdotoxin (0.1μM) did not cause any change of membrane potential. Component of 4-AP-sensitive Kv current was smaller in 1K,1C-GBH rat than in normotensive rat. The voltage dependence of steady-state activation and inactivation of Kv channel determined by using double-pulse protocol showed no significant difference. These results suggest that 4-AP-sensitive Kv channels play a major role in the regulation of membrane potential in cerebral arterial smooth muscle cells and alterations of 4-AP- sensitive K<SUB>V</SUB> channels would contribute to hypopolarization of membrane potential in 1K,1C-GBH rat.

Methylene Blue-stained Interstitial Cells are Electrically Active in the Myenteric Board Freshly Prepared from the Murine Small Intestine

Kyu Pil Lee,Ju-Hong Jeon,Insuk So,Ki Whan Kim 대한생리학회-대한약리학회 2006 The Korean Journal of Physiology & Pharmacology Vol.10 No.4

Many gastrointestinal muscles show electrical oscillation, so-called "slow wave", originated from interstitial cells of Cajal (ICCs). Thus, a technique to freshly isolate the cells is indispensable to explore the electrophysiological properties of the ICCs. To apply an enzyme solution on the serosal surface for cell isolation, the intestine was inverted and 0.02% trypsin solution and 0.04% collagenase solution were applied to serosal cavity. After the enzyme treatment, mucosal layer was removed and longitudinal muscle layer was gently separated from the rest of tissue. The thin layer was stretched in the recording chamber and mounted on an inverted microscope. Using β-escine, perforated whole cell patch clamp technique was used. Under a microscope, the tissue showed smooth muscle cells and interstitial cells around the myenteric plexus. Under voltage clamp condition, three types of membrane potential were recorded. One group of interstitial cells, which were positive to methylene blue and CD34, showed spontaneous outward current. These cells had bipolar shape and were considered as fibroblast-like cells because of their peculiar shape and arrangement. Another group, positive to c-kit and methylene blue, showed spontaneous inward current. These cells had more rounded shape and processes and were considered as ICCs. The third, positive to c-kit and had granules containing methylene blue, showed quiet membrane potentials under the voltage-clamp mode. These cells appeared to be resident macrophages. Therefore, in the freshly isolated thin tissue preparation, methylene blue could easily identify three types of cells rather than morphological properties. Using this method, we were able to study electrical properties of fibroblast and residential macrophage as well as myenteric ICCs.

Four active monomers from Moutan Cortex exert inhibitory effects against oxidative stress by activating Nrf2/Keap1 signaling pathway

Baoshun Zhang,Deqing Yu,Nanxuan Luo,Changqing Yang,Yurong Zhu 대한생리학회-대한약리학회 2020 The Korean Journal of Physiology & Pharmacology Vol.24 No.5

Paeonol, quercetin, β-sitosterol, and gallic acid extracted from Moutan Cortex had been reported to possess anti-oxidative, anti-inflammatory, and antitumor activities. This work aimed to illustrate the potential anti-oxidative mechanism of monomers in human liver hepatocellular carcinoma (HepG2) cells-induced by hydrogen peroxide (H₂O₂) and to evaluate whether the hepatoprotective effect of monomers was independence or synergy in mice stimulated by carbon tetrachloride (CCl₄). Monomers protected against oxidative stress in HepG2 cells in a doseresponse manner by inhibiting the generation of reactive oxygen species, increasing total antioxidant capacity, catalase and superoxide dismutase (SOD) activities, and activating the antioxidative pathway of nuclear factor E2-related factor 2/Kelchlike ECH-associated protein 1 (Nrf2/Keap1) signaling pathway. We found that the in vitro antioxidant capacities of paeonol and quercetin were better than those of -sitosterol and gallic acid. Furthermore, paeonol apparently diminished the levels of alanine transaminase and aspartate aminotransferase, augmented the contents of glutathione and SOD, promoted the expressions of Nrf2 and heme oxygenase-1 proteins in mice stimulated by CCl₄. In HepG2 cells, paeonol, quercetin, β-sitosterol, and gallic acid play a defensive role against H₂O₂-induced oxidative stress through activating Nrf2/Keap1 pathway, indicating that these monomers have anti-oxidative properties. Totally, paeonol and quercetin exerted anti-oxidative and hepatoprotective effects, which is independent rather than synergy.

Synergistic Induction of iNOS by IFN-g and Glycoprotein Isolated from Dioscorea batatas

Pham Thi Thu Huong,Min Young Lee,Kun Yeong Lee,In Youp Chang,Seog Ki Lee,Sang Pil Yoon,Dong-Cheol Lee,Young Jin Jeon 대한생리학회-대한약리학회 2012 The Korean Journal of Physiology & Pharmacology Vol.16 No.6

Dioscorea species continue to be used in traditional Chinese medicine, and represent a major source of steroid precursors for conventional medicine. In the previous study, We isolated glycoprotein (GDB) from Dioscorea batatas, characterized, and demonstrated immunostimulating activity in C57BL/6 mice. The aim of this study was to investigate the mechanism whereby GDB activates macrophages. Macrophages activation by GDB was investigated by analyzing the effects of GDB on nitric oxide (NO) production, iNOS expression, mitogen activated protein kinase (MAPK) phosphorylation, and transcription factor activation. In the presence of IFN-Ճ, GDB strongly stimulated macrophages to express iNOS and produce NO. Furthermore, the activation of p38 was synergistically induced by GDB plus IFN-Ճ, but SB203580 (a p38 inhibitor) inhibited GDB plus IFN-Ճ-induced p38 activation. This study indicates that GDB is an important activator of macrophages. Furthermore, due to the critical role that macrophage activation plays in innate immune response, the activation effects of GDB on macrophages suggest that GDB may be a useful immunopotentiating agent.