• YAKHAK HOEJI
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• v.43 no.1
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• pp.55-60
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• 1999

To investigate analgesic mechanism of capsaicin and its analogues (capaicinoids) adenosine release was measured by high performance liquid chromatography from rat spinal cord synaptosomes. Exposure of synaptosomes to $K^+$ and morphine produced a dose dependent release of adenosine in the presence of $Ca^{++}$. Capsaicin (0.1, 1, $10{\;}{\mu}M$), and its analogues: NE-19550 (1, 10, $100{\;}{\mu}M$), DMNE (1, 10, $100{\;}{\mu}M$) and KR 25018 (0.1, 1, $10{\;}{\mu}M$) produced a concentration dependent release of adenosine in the presence of $Ca^{++}$. Nifedifine, L-type voltage sensitive calcium channel blocker, inhibited $K^+$ (6, 12 mM)-and morphine ($10{\;}{\mu}M$)-evoked release of adenosine partially. Capsazepine, a novel capsaicin selective antagonist, blocked only capsaicin and capsaicinoids induced release of adenoside. Therefore, it is suggested that the adenosine release by capsaicin and capsaicinoids having antinociceptive effects involves actvation of capsaicin specific receptor and capsaicin sensitive $Ca^{++}$. channel.

• YAKHAK HOEJI
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• v.44 no.6
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• pp.499-504
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• 2000

We previously demonstrated that 6-paradol, a compound structurally related to capsaicin, showed to produce prolonged analgesia in experimental animals. The effects of 6-paradol on the release of adenosine were investigated in the rat spinal cord synaptosomes by high performance liquid chromatography. In the presence of $Ca^{++}$, adenosine was released from synaptosomes of rat spinal cord by 6-paradol and capsaicin in a dose dependent manner. Nifedifine, L-type voltage sensitive calcium channel blocker, was found to be ineffective in releasing adenosine by $10\;{\mu}M$ 6-paradol. After exposure to $10\;{\mu}M$ capsazepine, a novel capsaicin selective antagonist, the level of adenosine evoked by $10\;{\mu}M$ 6-paradol was decreased by 75%, and that evoked by $10\;{\mu}M$ capsaicin was blocked completely. These results suggest that the analgesic effect of 6-paradol might be mediated by the vanilloid (capsaicin) sensitive pathway, or the direct binding to the vanilloid receptor.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.3
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• pp.470-475
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• 2010

Calcium-channel blockers such as nifedipine could be associated with gingival overgrowth. The aim of this study was to examine the role of Paeonia lactiflora Pallas(PLP) on nifedipine-induced gingival hyperplasia along with submandibular secretory function in rats. Animals in divided groups received nifedipine (250 mg/kg) alone and in PLP(100, 200 mg/kg) in orally administration for 3 weeks. Pure submandibular saliva was collected intraorally by micropolyethylene cannula and the mandibular gingiva was examined by means of dissecting microscope for signs of redness, tickness, inflammation and exuda. Twenty-one days nifedipine treatment induced gingival hyperplasia accompanied with reduced salivary flow rate and concentrations total protein, epidermal growth factor(EGF) and calcium in comparison with normals. Co-treatment of animals with nifedifine and PLP protected from gingival hyperplasia and retained flow rate, and concentrations of total protein, EGF and calcium in normal levels.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.6
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• pp.375-379
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• 2003

$Ca^{2+}$ influx appears to be important for triggering myoblast fusion. It remains, however, unclear how $Ca^{2+}$ influx rises prior to myoblast fusion. Recently, several studies suggested that NMDA receptors may be involved in $Ca^{2+}$ mobilization of muscle, and that $Ca^{2+}$ influx is mediated by NMDA receptors in C2C12 myoblasts. Here, we report that other types of ionotropic glutamate receptors, non-NMDA receptors (AMPA and KA receptors), are also involved in $Ca^{2+}$ influx in myoblasts. To explore which subtypes of non-NMDA receptors are expressed in C2C12 myogenic cells, RT-PCR was performed, and the results revealed that KA receptor subunits were expressed in both myoblasts and myotubes. However, AMPA receptor was not detected in myoblasts but expressed in myotubes. Using a $Ca^{2+}$ imaging system, $Ca^{2+}$ influx mediated by these receptors was directly measured in a single myoblast cell. Intracellular $Ca^{2+}$ level was increased by KA, but not by AMPA. These results were consistent with RT-PCR data. In addition, KA-induced intracellular $Ca^{2+}$ increase was completely suppressed by treatment of nifedifine, a L-type $Ca^{2+}$ channel blocker. Furthermore, KA stimulated myoblast fusion in a dose-dependent manner. CNQX inhibited not only KA-induced myoblast fusion but also spontaneous myoblast fusion. Therefore, these results suggest that KA receptors are involved in intracellular $Ca^{2+}$ increase in myoblasts and then may play an important role in myoblast fusion.

• International Journal of Oral Biology
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• v.38 no.1
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• pp.5-12
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• 2013

Recent studies indicate that reactive oxygen species (ROS) can act as modulators of neuronal activity, and are critically involved in persistent pain primarily through spinal mechanisms. In this study, we investigated the effects of NaOCl, a ROS donor, on neuronal excitability and the intracellular calcium concentration ($[Ca^{2+}]_i$) in spinal substantia gelatinosa (SG) neurons. In current clamp conditions, the application of NaOCl caused a membrane depolarization, which was inhibited by pretreatment with phenyl-N-tert-buthylnitrone (PBN), a ROS scavenger. The NaOCl-induced depolarization was not blocked however by pretreatment with dithiothreitol, a sulfhydryl-reducing agent. Confocal scanning laser microscopy was used to confirm whether NaOCl increases the intracellular ROS level. ROS-induced fluorescence intensity was found to be increased during perfusion of NaOCl after the loading of 2',7'-dichlorofluorescin diacetate ($H_2DCF$-DA). NaOCl-induced depolarization was not blocked by pretreatment with external $Ca^{2+}$ free solution or by the addition of nifedifine. However, when slices were pretreated with the $Ca^{2+}$ ATPase inhibitor thapsigargin, NaOCl failed to induce membrane depolarization. In a calcium imaging technique using the $Ca^{2+}$-sensitive fluorescence dye fura-2, the $[Ca^{2+}]_i$ was found to be increased by NaOCl. These results indicate that NaOCl activates the excitability of SG neurons via the modulation of the intracellular calcium concentration, and suggest that ROS induces nociception through a central sensitization.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.4
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• pp.425-434
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• 1997

Many reports represent that angiotensin II (ANG II) caused a dose dependent biphasic effects on fluid transport in the proximal tubule. However, respective roles of different signaling pathways in mediating these effects remain unsettled. The aim of the present study was to examine signaling pathways at high doses of ANG II on the $Na^+$ uptake of primary cultured rabbit renal proximal tubule cells(PTCs) in hormonally defined serum-free medium. High concentrations of ANG II $(>10^{-9}\;M)$ inhibited $Na^+$ uptake and increased $[Ca^{2+}]_i\;level$ in the PTCs. However, low concentrations of $(<10^{-11}\;ANG\;II)$ stimulated $Na^+$ uptake and did not affect $[Ca^{2+}]_i\;level$. 8-(N, N-diethylamino)-octyl-3,3,5- trimethoxybenzoate (TMB-8), ethylene glycol-bis$({/beta}-amino\;ethyl ether)-N,N,N'$, N'-tetra acetic acid (EGTA), and nifedifine partially blocked the inhibitory effects of ANG II on $Na^+$ uptake. When ANG II and bradykinin (BK) were treated together, $Na^+$ uptake was further reduced $(88.47{\pm}1.98%\;of\;that\;of\;ANG\;II,\;81.85{\pm}1.84%\;of\;that\;of\;BK)$. In addition, W-7 and KN-62 blocked the ANG II-induced inhibition of $Na^+$ uptake. Arachidonic acid reduced $Na^+$ uptake in a dose-dependent manner. When ANG II and arachidonic acid were treated together, inhibitory effects on $Na^+$ uptake significantly exhibited greater reduction than that of each group, respectively. When PTCs were treated by mepacrine $(10^{-6}\;M)$ and AACOCF3 $(10^{-5}\;M)$ for 1 hr before the addition of $(<10^{-9}\;ANG\;II)$, the inhibitory effect of ANG II was reversed. In addition, econazole $(>10^{-6}\;M)$ blocked ANG II-induced inhibition of $Na^+$ uptake. In conclusion, the $[Ca^{2+}]_i$ (calcium-calmodulin-dependent kinase) and phospholipase $A_2\;(PLA_2)$ metabolites are involved in the inhibitory effects of ANG II on $Na^+$ uptake in the PTCs.