• The Korean Journal of Physiology and Pharmacology
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• 제6권4호
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• pp.207-214
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• 2002

The present study was designed to clarify whether tacrine affects the release of catecholamines (CA) from the isolated perfused model of rat adrenal gland or not and to elucidate the mechanism of its action. Tacrine $(3{\times}10^{-5}{\sim}3{\times}10^{-4}\;M)$ perfused into an adrenal vein for 60 min inhibited CA secretory responses evoked by ACh $(5.32{\times}10^{-3}\;M),$ DMPP (a selective neuronal nicotinic agonist, $10^{-4}$ M for 2 min) and McN-A-343 (a selective muscarinic M1-agonist, $10^{-4}$ M for 2 min) in relatively dose- and time- dependent manners. However, tacrine failed to affect CA secretion by high $K^+\;(5.6{\times}10^{-2}\;M).$ Tacrine itself at concentrations used in the present experiments did not also affect spontaneous CA output. Furthermore, in the presence of tacrine $(10^{-4}\;M),$ CA secretory responses evoked by Bay-K-8644 (an activator of L-type $Ca^{2+}$ channels, $10^{-4}\;M),$ but not by cyclopiazonic acid (an inhibitor of cytoplasmic $Ca^{2+}-ATPase,\;10^{-4}\;M),$ was relatively time-dependently attenuated. Also, physostigmine $10^{-4}\;M),$ given into the adrenal gland for 60 min, depressed CA secretory responses evoked by ACh, McN-A-343 and DMPP while did not affect that evoked by high $K^+.$ Collectively, these results obtained from the present study demonstrate that tacrine greatly inhibits CA secretion from the perfused rat adrenal gland evoked by stimulation of cholinergic (both nicotinic and muscarinic) receptors, but does fail to affect that by direct membrane-depolarization. It is suggested that this inhibitory effect of tacrine may be exerted by blocking both the calcium influx into the rat adrenal medullary chromaffin cells without $Ca^{2+}$ release from the cytoplasmic calcium store, that is relevant to the cholinergic blockade. Also, the mode of action between tacrine and physostigmine in rat adrenomedullary CA secretion seems to be similar.

• The Korean Journal of Physiology and Pharmacology
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• 제8권4호
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• pp.227-235
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• 2004

The aim of the present study was to examine the effect of leptin on CA release from the isolated perfused model of the rat adrenal gland, and to establish its mechanism of action. Leptin $(1{\sim}100\;ng/ml)$, when perfused into an adrenal vein of the rat adrenal gland for 60 min, enhanced a dose-dependently the secretory responses of CA evoked by ACh $(5.32{\times}10^{-3}\;M)$, DMPP $(10^{-4}\;M)$ and McN-A-343 $(10^{-4}\;M)$, although it alone has weak effect on CA secretion. However, it did not affect the CA secretion evoked by excess $K^+\;(5.6{\times}10^{-2}\;M)$. Leptin alone produced a weak secretory response of the CA. Moreover, leptin (10 ng/ml) in to an adrenal vein for 60 min also augmented the CA release evoked by BAY-K-8644, an activator of the dihydropyridine L-type $Ca^{2+}$ channels, and cyclopiazonic acid, an inhibitor of cytoplasmic $Ca^{2+}$ ATPase. However, in the presence of U0126 $(1\;{\mu}M)$, an inhibitor of mitogen-activated protein kinase (MAPK), leptin no longer enhanced the CA secretion evoked by ACh and DMPP. Furthermore, in the presence of anti-leptin (10 ng/ml), an antagonist of Ob receptor, leptin (10 ng/ml) also no longer potentiated the CA secretory responses evoked by DMPP and Bay-K-8644. Collectively, these experimental results suggest that leptin enhances the CA secretion from the rat adrenal medulla evoked by cholinergic stimulation (both nicotininc and muscarinic receptors), but does not that by membrane depolarization. It seems that this enhanced effect of leptin may be mediated by activation of U0126-sensitive MAPK through the leptin receptors, which is probably relevant to the activation of the dihydropyridine L-type $Ca^{2+}$ channels located on the rat adrenomedullary chromaffin cells.

• The Korean Journal of Physiology and Pharmacology
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• 제1권5호
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• pp.485-493
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• 1997

We investigated the effect of ${\alpha}-adrenergic$ and cholinergic receptor agonists on $Ca^{2+}$ current in adult rat trigeminal ganglion neurons using whole-cell patch clamp methods. The application of acetylcholine, carbachol, and oxotremorine ($50\;{\mu}M\;each$) produced a rapid and reversible reduction of the $Ca^{2+}$ current by $17{\pm}6%,\;19{\pm}3%,\;and\;18{\pm}4%$, respectively. Atropine, a muscarinic antagonist, blocked carbachol- induced $Ca^{2+}$ current inhibition to $3{\pm}1%$. Norepinephrine ($50\;{\mu}M$) reduced $Ca^{2+}$ current by $18{\pm}2%$, while clonidine ($50\;{\mu}M$), an ${\alpha}2-adrenergic$ receptor agonist, inhibited $Ca^{2+}$ current by only $4{\pm}1%$. Yohimbine, an ${\alpha}2-adrenergic$ receptor antagonist, did not block the inhibitory effect of norepinephrine on $Ca^{2+}$ current, whereas prazosin, an ${\alpha}1-adrenergic$ receptor antagonist, attenuated the inhibitory effect of norepinephrine on $Ca^{2+}$ current to $6{\pm}1%$. This pharmacology contrasts with ${\alpha}2-adrenergic$ receptor modulation of $Ca^{2+}$ channels in rat sympathetic neurons, which is sensitive to clonidine and blocked by yohimbine. Our data suggest that the modulation of voltage dependent $Ca^{2+}$ channel by norepinephrine is mediated via an α1-adrenergic receptor. Pretreatment with pertussis toxin (250 ng/ml) for 16 h greatly reduced norepinephrine- and carbachol-induced $Ca^{2+}$ current inhibition from $17{\pm}3%\;and\;18{\pm}3%\;to\;2{\pm}1%\;and\;2{\pm}1%$, respectively. These results demonstrate that norepinephrine, through an ${\alpha}1-adrenergic$ receptor, and carbachol, through a muscarinic receptor, inhibit $Ca^{2+}$ currents in adult rat trigeminal ganglion neurons via pertussis toxin sensitive GTP-binding proteins.

• The Korean Journal of Physiology and Pharmacology
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• 제15권6호
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• pp.333-338
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• 2011

Black ginseng (BG) has been widely used as herbal treatment for improving physiological function. In order to investigate the neuroprotective action of this herbal medicine, we examined the influence of BG on the learning and memory of rats using the Morris water maze, and we studied the effects of BG on the central cholinergic system and neural nitric oxide synthesis in the hippocampus of rats with neuronal and cognitive impairment. After middle cerebral artery occlusion was applied for 2h, the rats were administered BG (100 or 400 $mgkg^{-1}$, p.o.) daily for 2 weeks, followed by training and performance of the Morris water maze test. The rats with ischemic insults showed impaired learning and memory on the tasks. Treatment with BG produced improvement in the escape latency to find the platform. Further, the BG groups showed a reduced loss of cholinergic immunoreactivity and nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d)-positive neurons in the hippocampus compared to that of the ISC group. These results demonstrated that BG has a protective effect against ischemia-induced neuronal and cognitive impairment. Our results suggest that BG might be useful for the treatment of vascular dementia.

• Archives of Pharmacal Research
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• 제28권6호
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• pp.699-708
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• 2005

The present study was designed to investigate the effect of naloxone, a well known opioid antagonist, on the secretion of catecholamines (CA) evoked by cholinergic stimulation and membrane-depolarization in the isolated perfused rat adrenal glands, and to establish its mechanism of action. Naloxone ($10^{-6}\~10^{-5}$ M), perfused into an adrenal vein for 60 min, produced dose- and time-dependent inhibition of CA secretory responses evoked by ACh ($5.32\times10^{-3}$ M), high K+ ($5.6\times10^{-2}$ M), DMPP ($10^{-4}$ M) and McN-A-343 ($10^{-4}$ M). Naloxone itself also failed to affect the basal CA output. In adrenal glands loaded with naloxone ($3\times10^{-6}$ M), the CA secretory responses evoked by Bay-K-8644, an activator of L-type $Ca^{2+}$ channels, and cyclopiazonic acid, an inhibitor of cytoplasmic $Ca^{2+}$-ATPase, were also inhibited. In the presence of met-enkephalin ($5\times10^{-6}$ M), a well known opioid agonist, the CA secretory responses evoked by ACh, high $K^+$, DMPP, McN-A-343, Bay-K-8644 and cyclopiazonic acid were also significantly inhibited. Taken together, these results suggest that naloxone greatly inhibits the CA secretion evoked by stimulation of cholinergic (both nicotinic and muscarinic) receptors as well as that by membrane depolarization. It seems that these inhibitory effects of naloxone does not involve opioid receptors, but might be mediated by blocking both the calcium influx into the rat adrenal medullary chromaffin cells and the uptake of $Ca^{2+}$ into the cytoplasmic calcium store, which are at least partly relevant to the direct interaction with the nicotinic receptor itself.

• Archives of Pharmacal Research
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• 제12권3호
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• pp.166-175
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• 1989

In the previous observations, it was reported that both total ginseng saponin and panaxadiol revealed the marked secretory effect of catecholamines (CA) from the rabbit adrenal gland and that CA secretion induced by them is due to dual mechanisms, cholinergic action and the direct action. In the present study, an attempt to investigate the effect of panaxatriol-type saponin (PT), which is known as an active component of Korean ginseng, on the secretion of CA from the rabbit adrenal gland was made. PT(200 $\mu$g) administered into adrenal vein evoked significantly secretion of CA from the isolated perfused rabbit adrenal gland. Secretory effect of CA produced by PT was attenuated clearly by treatment with chlorisondamine or adenosine, but was markedly increased by physostigmine. Perfusion of Krebs solution containing PT (200 $\mu$g) for 30 min potentiated greatly secretion of CA induced by acetylcholine. PT-induced CA secretion was weakened considerably by ouabain treatement or perfusion of calcium-free Krebs solution. These experimental data demonstrate that PT releases CA from the isolated perfused rabbit adrenal gland by a calcium-dependentd exocytotic mechanism. It seems that the secretory effect of PT is caused through the release of acetylcholine form cholinergic terminals present in the adrenal gland and a direct action on the chromaffin cell itself.

• Natural Product Sciences
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• 제13권1호
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• pp.68-77
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• 2007

The aim of the present study was to examine the effects of green tea extract (CUMS6335) on the release of CA evoked by cholinergic stimulation and direct membrane-depolarization in the perfused model of the adrenal gland isolated from the spontaneously hypertensive rats (SHRs), and to establish the mechanism of action. Furthermore, it was also to test whether there is species difference between animals, and between CUMS6335 and EGCG, one of biologically the most powerful catechin compounds found in green tea. CUMS6335 $(100\;{\mu}g/ml)$, when perfused into an adrenal vein for 60 min, time-dependently inhibited the CA secretory responses evoked by ACh (5.32mM), high $K^+$(56 mM), DMPP $(100\;{\mu}M)$, and McN-A-343 $(100\;{\mu}M)$ from the isolated perfused adrenal glands of SHRs. However, CUMS6335 itself did fail to affect basal catecholamine output. Also, in adrenal glands loaded with CUMS6335 $(100\;{\mu}g/ml)$, the CA secretory responses evoked by Bay-K-8644 $(10\;{\mu}M)$ and cyclopiazonic acid $(10\;{\mu}M)$ were also inhibited in a relatively time-dependent fashion. However, in the Presence of EGCG $(8.0\;{\mu}g/ml)$ for 60 min, the CA secretory response evoked by ACh, high $K^+$, DMPP, McN-A-343, Bay-K-8644 and cyclopiazonic acid were not affected except for last period. Collectively, these results indicate that CUMS6335 inhibits the CA secretion evoked by stimulation of cholinergic (both nicotinic and muscarinic) receptors as well as by direct membrane-depolarization from the perfused adrenal gland of the SHR. It seems that this inhibitory effect of CUMS6335 is exerted by blocking both the calcium influx into the rat adrenal medullary chromaffin cells and the uptake of $Ca^{2+}$ into the cytoplasmic calcium store, which are at least partly relevant to the direct interaction with the nicotinic receptor itself. It seems likely that there is much difference in mode of the CA-releasing action between CUMS6335 and EGCG.

• Biomolecules & Therapeutics
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• 제12권3호
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• pp.165-174
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• 2004

The aim of the present study was to investigate the effect of FCCP (carbonyl cyanide p-trifluoromethoxyphenyIhydrazone), which is a potent mitochondrial uncoupler, on secretion of catecholamines (CA) from the perfused model of the rat adrenal gland and to establish the mechanism of its action. The perfusion of FCCP (3 ${\times}$ $10^{-5}$ M) into an adrenal vein of for 90 min resulted in great increases in CA secretions. Tachyphylaxis to CA-releasing effect of FCCP was not observed by repeated perfusion of it. The CA-releasing effects of FCCP were depressed by pre-treatment with pirenzepine, chlorisondamine, nicardipine, TMB-8, and the perfusion of EGTA plus $Ca^{2+}$-free medium. In the presence of FCCP (3 ${\times}$ $10^{-5}$ M), the CA secretory responses induced by Ach (5.32 ${\times}$ $10^{-3}$ M), and DMPP ($10^{-4}$ M) were significantly enhanced. Furthermore, the perfusion of CCCP (3 ${\times}$ $10^{-5}$ M), a similar mitochondrial uncoupler, into an adrenal vein for 90 min also caused an increased response in CA secretion. Taken together these experimental results indicate that FCCP causes the CA secretion the perfused rat adrenal medulla in a calcium-dependent fashion. It is suggested that this facilitatory effects of FCCP may be mediated by cholinergic receptor stimulation, which is relevant to both stimulation of the $Ca^{2+}$ influx and $Ca^{2+}$ release from cytoplasmic $Ca^{2+}$ stores.

• 한국동물학회지
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• 제38권2호
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• pp.248-268
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• 1995

출생 후 0일, 7일, 14일, 21일 그리고 성체의 흰쥐 전뇌 기저부의 내측중격핵과 수직 및 수평대각 Broca대에서 choline acetyltransferase(ChAT)에 면역반응을 보이는 신경조직과 세포의 분화를 면역조직화학적 및 전자현미경적 방법을 이용하여 조사하였다. 출생 후 초기와 성체에서 신경세포의 세포질과 수상돌기에서 고루 ChAT 면역반응이 확인되었다. 뇌 기저부의 ChAT 면역반응 신경세포들은 발생에 따른 뇌 크기의 증대와 뇌 조직의 분화에 따라 점차 수적 증가를 보였다. 이 ChAT 면역반응 신경세포들은 세포의 모양과 세포제의 장 · 단축의 비에 따라 6가지 형 즉 1) 월형 2) 난형, 3) 세장형, 4) 방추형. 5) 삼각형, 6) 다각형으로 분류되었다 전뇌 기저 핵에서 원형과 난형 신경세포들의 출현율은 출생 후 0일에서 높았으나 성체로 되면서 감소된 반면, 세장형. 방추형. 삼각형 그리고 다각형 신경세포들의 출현율은 출생 후 0일에서는 낮았으나 성체로 되면서 증가하였다. 모든 핵들에서 ChAT 면역반응 신경세포체의 부피는 출생 후 0일에 996-1,252 Um3로 제일 작았으며, 내측중격핵과 수직대각 Broca대 그리고 수평대각 Broca대에서는 출생 후 21일에 각각 5,061, 5.701, 5,820 um3로 최대치를 보였다. 그후 성체로 되면서 모든 핵에서1,897-2,704 roms로 다시 감소하였다. 전자현미경적 관찰에서 출생 후 21일된 흰쥐 수평대각 Broca대에서 ChAT 면역반응은 핵의 핵질 일부와 핵막 그리고 미토콘드리아와 조면소포체에서 관찰되었다. 이 결과들로 미루어 출생 후 초기 발생단계에서 흰쥐 전뇌 기저부의 내측중격핵과 수직 및 수평대각 Broca대에서 ChAT 면역반응 신경세포들은 축삭과 수상돌기의 형성에 따라 세포의 형과 그 출현율 및 세포제의 크기에서 현저한 변화가 이루어지는 것으로 생각된다.

• The Korean Journal of Physiology and Pharmacology
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• 제20권4호
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• pp.407-414
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• 2016

This study was performed to investigate whether the spinal cholinergic and serotonergic analgesic systems mediate the relieving effect of electroacupuncture (EA) on oxaliplatin-induced neuropathic cold allodynia in rats. The cold allodynia induced by an oxaliplatin injection (6 mg/kg, i.p.) was evaluated by immersing the rat's tail into cold water ($4^{\circ}C$) and measuring the withdrawal latency. EA stimulation (2 Hz, 0.3-ms pulse duration, 0.2~0.3 mA) at the acupoint ST36, GV3, or LI11 all showed a significant anti-allodynic effect, which was stronger at ST36. The analgesic effect of EA at ST36 was blocked by intraperitoneal injection of muscarinic acetylcholine receptor antagonist (atropine, 1 mg/kg), but not by nicotinic (mecamylamine, 2 mg/kg) receptor antagonist. Furthermore, intrathecal administration of $M_2$ (methoctramine, $10{\mu}g$) and $M_3$ (4-DAMP, $10{\mu}g$) receptor antagonist, but not $M_1$ (pirenzepine, $10{\mu}g$) receptor antagonist, blocked the effect. Also, spinal administration of $5-HT_3$ (MDL-72222, $12{\mu}g$) receptor antagonist, but not $5-HT_{1A}$ (NAN-190, $15{\mu}g$) or $5-HT_{2A}$ (ketanserin, $30{\mu}g$) receptor antagonist, prevented the anti-allodynic effect of EA. These results suggest that EA may have a significant analgesic action against oxaliplatin-induced neuropathic pain, which is mediated by spinal cholinergic ($M_2$, $M_3$) and serotonergic ($5-HT_3$) receptors.