• Proceedings of the PSK Conference
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• 2002.10a
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• pp.131-133
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• 2002

In 'Nature', Dixon et al. reported the first cloned mammalian G-protein coupled receptor sequence (1). The DNA sequence from a hamster encodes the $\beta$$_2$-aderenergic receptor. In the same year, 1986, Kubo et al. published the muscarinic acetylcholine receptor sequence (M$_1$) from a rat in the same journal (2). Both groups purified the receptor proteins and identified the DNA sequences (1, 2). (omitted)

• Biomolecules & Therapeutics
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• v.1 no.1
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• pp.1-8
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• 1993

It has been known that calcium antagonists also inhibit the radioligand binding to muscarinic and $\alpha$-adrenergic receptors and, in case of verapamil, these inhibitions may play a role in the effects of verapamil on the heart. In this study, the effects of nicardipine, nifedipine, nimodipine, diltiazem and verapamil on the binding of [$^3H$]dihydroalprenolol (DHA) to dog cardiac ${\beta}$-adrenergic receptors were examined. A single uniform [$^3H$]DHA binding site ($K_D/= 5nM\;and\;B_{max}=2600$ fmol/mg protein) was identified in dog cardiac sarcolemma. [$^3H$]DHA binding was not affected by the usual therapeutic concentrations of these calcium antagonists (nanomolar range) but in the "nonspecific"concentration ranges ($28-180{\mu}m$) these drugs inhibited [$^3H$]DHA binding to $\beta$-adrenergic receptors. Nicardipine, nifedipine, nimodipine and diltiazem competed for [$^3H$]DHA binding to ${\beta}$-adrenergic receptors with dissociation constants ($K_i$) of $28{\mu}m,\' 74{\mu}m, 39{\mu}m \;and \;35{\mu}m,$ respectively. Verapamil ($K_i=176.5 {\mu}m$) was less potent inhibitor than other drugs and this inhibition was noncompetitive; the maximal binding capacity ($B_{max}$) $300 {\mu}m$ verapamil without change in the apparent dissociation constant (4K_D$) for DHA. These results indicate that the inhibitory action of calcium antagonists at high concentrations on ${\beta}$-adrenergic receptors is not involved in the therapeutic effects of these drugs by the calcium channel blocking action.

• Archives of Pharmacal Research
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• v.25 no.6
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• pp.932-939
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• 2002

The aim of the present study was to determine the characteristics of cytisine on the secretion of catecholamines (CA) in isolated perfused rat adrenal glands, and to clarify its mechanism of action. The release of CA evoked by the continuous infusion of cytisine ($1.5{\times}10^{-5} M$) was time-dependently reduced from 15 min following the initiation of cytisine infusion. Furthermore, upon the repeated injection of cytisine ($5{\times}10^{-5}$), at 30 min intervals into an adrenal vein, the secretion of CA was rapidly decreased following the second injection. Tachyphylaxis to the release of CA was observed by the repeated administration of cytisine. The cytisine-induced secretion of CA was markedly inhibited by pretreatment with chlorisondamine, nicardipine, TMB-8, and the perfusion of $Ca^{2+}$-free Krebs solution, while it was not affected by pirenzepine or diphenhydramine. Moreover, the secretion of CA evoked by ACh was time-dependently inhibited by the prior perfusion of cytisine ($5{\times}10^{-6} M$). Taken together, these experimental data suggest that cytisine causes secretion of catecholamines from the perfused rat adrenal glands in a calcium-dependent fashion through the activation of neuronal nicotinic ACh receptors located in adrenomedullary chromaffin cells. It also seems that the cytisine-evoked release of catecholamine is not relevant to the activation of cholinergic M$_1$-muscarinic or histaminergic receptors.

• Korean Journal of Pharmacognosy
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• v.21 no.2
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• pp.173-178
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• 1990

This study was attempted to examine the effect of Sopung-Tang(SPT) on the arterial blood pressure in rats and to elucidate its mechanism of action. SPT given into a femoral vein produced a dose-related vasopressor responses followed by vasodepressor responses. SPT-induced hypotension was significantly inhibited by pretreatment with atropine or propranolol while was not affected by chlorisondamine, Prazosin and cyproheptadine. SPT-evoked hypertensive activity was markedly blocked by pretreatment with prazosin but was not influenced by atropine, chlorisondamine, propranolol and cyproheptadine. Infusion of SPT(15.0 mg/kg/30min) did not affect norepinephrine-induced pressor responses. These experimental results suggest that SPT causes biphasically initial hypertensive activity followed by hypotensive activity, and that this hypertension may be due to the stimulation of peripheral adrenergic alpha-receptors and hypotension may be elicited through stimulation of peripheral cholinergic muscarinic receptors and adrenergic beta-receptors.

• The Korean Journal of Physiology and Pharmacology
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• v.20 no.4
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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.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.4
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• pp.231-238
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• 2003

The present study was undertaken to investigate the effect of bradykinin on secretion of catecholamines (CA) evoked by stimulation of cholinergic receptors and membrane depolarization from the isolated perfused model of the rat adrenal glands, and to elucidate its mechanism of action. Bradykinin $(3{\times}10^{-8}M)$ alone produced a weak secretory response of the CA. however, the perfusion with bradykinin $(3{\times}10^{-8}M)$ into an adrenal vein of the rat adrenal gland for 90 min enhanced markedly the secretory responses of CA evoked by ACh $(5.32{\times}10^{-3}M)$, excess $K^+$ ($5.6{\times}10^{-2}M$, a membrane depolarizer), DMPP ($10^{-4}$ M, a selective neuronal nicotinic agonist) and McN-A-343 ($10^{-4}$ M, a selective M1-muscarinic agonist). Moreover, bradykinin ($3{\times}10^{-8}$ M) in to an adrenal vein for 90 min also augmented the CA release evoked by BAY-K-8644, an activator of the dihydropyridine L-type $Ca^{2+}$ channels. However, in the presence of $(N-Methyl-D-Phe^7)$-bradykinin trifluoroacetate salt $(3{\times}10^{-8}M)$, an antagonist of $BK_2$-bradykinin receptor, bradykinin no longer enhanced the CA secretion evoked by Ach and high potassium whereas the pretreatment with Lys-$(des-Arg^9,\;Leu^9)$-bradykinin trifluoroacetate salt $(3{\times}10^{-8}M)$, an antagonist of $BK_1$-bradykinin receptor did fail to affect them. Furthermore, the perfusion with bradykinin $(3{\times}10^{-6}M)$ into an adrenal vein of the rabbit adrenal gland for 90 min enhanced markedly the secretory responses of CA evoked by excess $K^+$ $(5.6{\times}10^{-2}M)$. Collectively, these experimental results suggest that bradykinin enhances the CA secretion from the rat adrenal medulla evoked by cholinergic stimulation (both nicotininc and muscarinic receptors) and membrane depolarization through the activation of $B_2$-bradykinin receptors, not through $B_1$-bradykinin receptors. This facilitatory effect of bradykinin seems to be associated to the increased $Ca^{2+}$ influx through the activation of the dihydropyridine L-type $Ca^{2+}$ channels.

• The Korean Journal of Pain
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• v.21 no.1
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• pp.27-32
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• 2008

Background: Experimental evidence indicates that ginseng modulate the nociceptive transmission. Authors examined the role of adrenergic and cholinergic receptors on the antinociceptive action of Korean red ginseng against the formalin-induced pain at the spinal level. Methods: Catheters were inserted into the intrathecal space of male Sprague-DawIey rats. Fifty ${\mu}l$ of 5% formalin solution was injected to the hindpaw for induction of pain and formalin-induced pain (flinching response) was observed. The role of spinal adrenergic and cholinergic receptors on the effect of Korean red ginseng was assessed by antagonists (Prazosin, yohimbine, atropine and mecamylamine). Results: Intrathecal Korean red ginseng produced a dose-dependent suppression of the flinching response in the rat formalin test. All of prazosin, yohimbine, atropine and mecamylamine antagonized the antinociception of Korean red ginseng. Conclusions: Spinal Korean red ginseng is effective against acute pain and facilitated pain state evoked by formalin injection. All of alpha 1, alpha 2, muscarinic and nicotinic receptors may play an important role in the antinociceptive action of Korean red ginseng at the spinal level.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.2
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• pp.147-154
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• 1998

It was attempted to clarify the participation of $K^+-channels$ in the post-receptor mechanisms of the muscarinic and $A_1-adenosine$ receptor- mediated control of acetylcholine (ACh) release in the present study. Slices from the rat hippocampus were equilibrated with $[^3H]$choline and the release of the labelled products was evoked by electrical stimulation (3 Hz, 5 V/cm, 2 ms, rectangular pulses), and the influence of various agents on the evoked tritium-outflow was investigated. Oxotremorine (Oxo, $0.1{\sim}10\;{\mu}M$), a muscarinic agonist, and $N^6-cyclopentyladenosine$ (CPA, $1{\sim}30\;{\mu}M$), a specific $A_1-adenosine$ agonist, decreased the ACh release in a dose-dependent manner, without affecting the basal rate of release. 4-aminopyridine (4AP), a specific A-type $K^+-channel$ blocker ($1{\sim}100\;{\mu}M$), increased the evoked ACh release in a dose-related fashion, and the basal rate of release is increased by 3 and $100\;{\mu}M$. Tetraethylammonium (TEA), a non-specific $K^+-channel$ blocker ($0.1{\sim}10\;{\mu}M$), increased the evoked ACh release in a dose-dependent manner without affecting the basal release. The effects of Oxo and CPA were not affected by $3\;{\mu}M$ 4AP co-treatment, but 10 mM TEA significantly inhibited the effects of Oxo and CPA. 4AP ($10\;{\mu}M$)- and TEA (10 mM)-induced increments of evoked ACh release were completely abolished in Ca^{2+}-free$ medium, but these were recoverd in low Ca^{2+}$ medium. And the effects of $K^+-channel$ blockers in low Ca^{2+}$ medium were inhibited by $Mg^{2+}$ (4 mM) and abolished by $0.3\;{\mu}M$ tetrodotoxin (TTX). These results suggest that the changes in TEA-sensitive potassium channel permeability and the consequent limitation of Ca^{2+}$ influx are partly involved in the presynaptic modulation of the evoked ACh-release by muscarinic and $A_1-adenosine$ receptors of the rat hippocampus.

• Journal of Life Science
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• v.25 no.10
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• pp.1103-1109
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• 2015

Cholinergic innervation of the hippocampus is known to be correlated with learning and memory. The cholinergic agonist carbachol (CCh) modulate synaptic plasticity and produced long-term synaptic depression (LTD) in the hippocampus. However, the exact mechanisms by which the cholinergic system modifies synaptic functions in the hippocampus have yet to be determined. This study introduces an acetylcholine receptor-mediated LTD that requires internalization of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptors on the postsynaptic surface and their intracellular mechanism in the hippocampus. In the present study, we showed that the application of the cholinergic agonist CCh reduced the surface expression of GluA2 on synapses and that this reduction was prevented by the M1 muscarinic acetylcholine receptor antagonist pirenzepine in primary hippocampal neurons. The interaction between GluA2 and the glutamate receptor-interacting protein 1 (GRIP1) was disrupted in a hippocampal slice from a rat upon CCh simulation. Under the same conditions, the binding of GluA2 to adaptin-α, a protein involved in clathrin-mediated endocytosis, was enhanced. The current data suggest that the activation of LTD, mediated by the acetylcholine receptor, requires the internalization of the GluA2 subunits of AMPA receptors and that this may be controlled by the disruption of GRIP1 in the PDZ ligand domain of GluA2. Therefore, we can hypothesize that one mechanism underlying the LTD mediated by the M1 mAChR is the internalization of the GluA2 AMPAR subunits from the plasma membrane in the hippocampal cholinergic system.

• The Korean Journal of Physiology and Pharmacology
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• v.9 no.4
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• pp.223-230
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• 2005

The purpose of the present study was to examine the effect of naltrexone, an opioid antagonist, on secretion of catecholamines (CA) evoked by cholinergic nicotinic stimulation and membrane-depolarization from the isolated perfused rat adrenal gland and to establish the mechanism of its action. Naltrexone $(3{\times}10^{-6}M)$ perfused into an adrenal vein for 60 min produced time-dependent inhibition in CA secretory responses evoked by ACh $(5.32{\times}10^{-3}M)$ , high $K^+$ $(5.6{\times}10^{-2}M)$ , DMPP ($10^{-4}$ M) and McN-A-343 $(10^{-4}M)$ . Naltrexone itself did also fail to affect basal CA output. In adrenal glands loaded with naltrexone $(3{\times}10^{-6}M)$ , 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. However, in the presence of met-enkephalin $(5{\times}10^{-6}M)$ , 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. Collectively, these experimental results demonstrate that naltrexone inhibits greatly CA secretion evoked by stimulation of cholinergic (both nicotinic and muscarinic) receptors as well as that by membrane depolarization. It seems that this inhibitory effect of naltrexone 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.