ライフサイエンスコーパス: epibatidine

1 AChRs exhibit high-affinity binding for [3H]epibatidine.

2 binding affinity at alpha4beta2-nAChRs than epibatidine.

3 ite, as expected from their competition with epibatidine.

4 cetylcholine, and the potent nicotine analog epibatidine.

5 alpha(7) K(i) ratio of 14,000, twice that of epibatidine.

6 ns showed affinities at the nAChR similar to epibatidine.

7 a(4)beta(2) nAChR receptors labeled by [(3)H]epibatidine.

8 ceptors show markedly reduced sensitivity to epibatidine.

9 affinity for alpha-bungarotoxin rather than epibatidine.

10 M, as measured by competition with (+/-)-[3H]epibatidine.

11 ing sites with differing affinities for [3H]-epibatidine.

12 of nicotinic receptors capable of binding 3H-epibatidine.

13 icotine, acetylcholine, carbamylcholine, and epibatidine.

14 l showed low affinity for nAChRs relative to epibatidine.

15 tivity to the nonselective nicotinic agonist epibatidine.

16 ydrogen bond further augments the binding of epibatidine.

17 , but wraps around the agonists lobeline and epibatidine.

18 hosteric nAChR binding site labeled by [(3)H]epibatidine.

19 before and after exposure of the columns to epibatidine.

20 While NIC (10-30 microM) and epibatidine (0.01-0.1 microM) fully activated human musc

21 rsal root ganglion neurons in culture, (+/-)-epibatidine (1 microM) was able to inhibit the capsaicin

22 e chloro analogue (5a, K(i) = 245 nM) 5a and epibatidine (1) produced dose-dependent analgesia in bot

23 In diabetic animals an agonist (epibatidine, 10(-10) mol/L) or antagonist (hexamethonium

24 Epibatidine (100 nM) induced an increase to an average o

25 ption induced by (+)-epibatidine but not (-)-epibatidine (12 microg/kg, s.c.).

26 ed the same rank orders of potency for (+/-)-epibatidine, 2S-(-)-nicotine, 7R,9S-(-)-cytisine, and 1,

27 The agonists epibatidine, 3-[2(S)-azetidinylmethoxy]pyridine (A-85380

28 In ligand binding studies, [3H]epibatidine ([3H]EB) binds with an affinity of approxima

29 of the sites in the retina measured with [3H]epibatidine ([3H]EB) is approximately 30% higher than wi

30 rdering of potencies in displacing (+/-)-[3H]epibatidine, (-)-[3H]cytisine or (-)-[3H]nicotine bindin

31 ravenous administration matched those of [3H]epibatidine, [3H]norchloroepibatidine, and (+/-)-exo-2-(

32 pical potent nicotinic analgesic agent (+/-)-epibatidine, 5 shows diminished activity in models of pe

33 f 28 microM for acetylcholine, 24 nM for (+)-epibatidine, 6.6 microM cytisine, and 15 microM 1,1-dime

34 and 12 pM, respectively, similar to that of epibatidine (8 pM).

35 Among them is epibatidine, a nicotinic acetylcholine receptor (nAChR)

36 We also determined the structure with bound epibatidine, a potent AChR agonist.

37 The nicotine analogue epibatidine achieves its high potency by taking advantag

38 Application of agonists (nicotine, cytisine, epibatidine) activated a large (100-200 pA/pF) inwardly

39 The overall data show that epibatidine activates muscle receptors by binding with h

40 line receptor binding was measured using [3H]epibatidine after deletion of alpha7, beta2, or beta4 su

41 (-)-nicotine, cytisine, carbachol, and (+/-)-epibatidine all stimulated 86Rb+ efflux, which was block

42 veral of the analogues were equal to that of epibatidine, all of the compounds were weak agonists in

43 Use of [3H]epibatidine allowed detailed characterization of multipl

44 AT-1001 competes with epibatidine, allowing for [(3)H]epibatidine binding to b

45 icotine, like the structurally similar toxin epibatidine, also distinguishes by binding affinity two

46 he alpha 4 beta 2 subtype, placing them with epibatidine among the most potent nAChR ligands describe

47 xpression of nAChRs in monkeys, we used 125I-epibatidine, an agonist at nAChRs containing alpha2 to a

48 These epibatidine analogs have been shown previously to posses

49 ridinyl)-7-azabicyclo[2.2.1]heptane (2i), an epibatidine analogue possessing an electron-releasing am

50 Compound 2i was also the most selective epibatidine analogue with a K(i) of 0.001 nM at alphabet

51 Conformationally constrained epibatidine analogues 20a,b and 23a,b were synthesized u

52 Epibatidine analogues 3- 5, possessing the pyridine ring

53 2'-Fluoro-3-(substituted pyridine)epibatidine analogues 7a-e and 8a-e were synthesized, an

54 With the exception of 1f and 1g, all the epibatidine analogues are full agonists (tail flick test

55 f 2,4-methanoproline) and provides access to epibatidine analogues containing heterocyclic substituen

56 2,3-Disubstituted epibatidine analogues possessing a 2'-amino group combin

57 A series of 2'-substituted-3'-phenyl epibatidine analogues were synthesized and evaluated for

58 A number of 2',3'-disubstituted epibatidine analogues were synthesized and evaluated in

59 d 6 was the key intermediate used to prepare epibatidine analogues where the 2'-chloro group on the p

60 Even though the conformationally restricted epibatidine analogues, 3- 7, and the benzo analogue 8a p

61 Two epibatidine analogues, 6 and 7, which have the 2'-chloro

62 induced by other nicotinic agonists (such as epibatidine, anatoxin, or cytisine) was also powerfully

63 The syntheses of (+/-)-epibatidine and (+/-)-epiboxidine have been accomplished

64 as evaluated by autoradiography using (125)I-epibatidine and (125)I-alphabungarotoxin, respectively.

65 We used [3H]epibatidine and 125I-alpha-bungarotoxin, together with s

66 In addition, (125)I-epibatidine and [(125)I]alpha-bungarotoxin binding in th

67 gic receptors labeled with the ligands [(3)H]epibatidine and [(3)H]AFDX-384 were affected to a much g

68 ha 7, beta 2, and beta 4 mRNA, or in [(125)I]epibatidine and [(3)H]nicotine binding between +/T and +

69 alpha-CtxMII inhibition of striatal 125I-epibatidine and [125I]A-85380 binding with alpha-CtxMII

70 twice daily for 2 weeks decreased both 125I-epibatidine and [125I]iodo-3-[2(S)-azetidinylmethoxy]pyr

71 into the C5 position of the pyridyl ring of epibatidine and A-84543 significantly increased the sele

72 tine were equal to bFGF and were mimicked by epibatidine and blocked by hexamethonium.

73 The present study compares epibatidine and carbamylcholine binding in terms of thei

74 s reveal opposite site selectivities between epibatidine and carbamylcholine; for epibatidine the ran

75 (+)- and (-)-Epibatidine and compounds 1b-d and 1i all possess simila

76 Moreover, unlike epibatidine and cytisine, 5-[(125)I]iodo-A-85380 shows n

77 xpressed human alpha4beta2 nAChRs with [(3)H]epibatidine and identified by Edman degradation the phot

78 PC12 cells were measured by binding with [3H]epibatidine and in functional studies with agonist-stimu

79 ylcholine receptor (nAChR) agonists, such as epibatidine and its molecular derivatives, are potential

80 Occupation by nicotinic agonists, epibatidine and lobeline, and nicotinic antagonists, met

81 binding sites in the brain and indicate that epibatidine and mecamylamine act as 5-HT(3)R antagonists

82 Epibatidine and mecamylamine are ligands used widely in

83 Previous studies that depended on epibatidine and mecamylamine as nAChR-specific ligands,

84 herapeutic agents and also toxicants such as epibatidine and neonicotinoid insecticides with a chloro

85 satisfactory concentration-response data for epibatidine and several other nicotinic agonists.

86 precipitation assays with iodine-125-labeled epibatidine and solubilized human neuroblastoma acetylch

87 rtant for the binding of the larger agonists epibatidine and varenicline, but dispensable for binding

88 of anisotropy were assessed for one agonist (epibatidine) and two antagonists (alpha-bungarotoxin and

89 Arecolone, (+)-epibatidine, and (+/-)-epibatidine were agonists with ac

90 nes, arecolone, eserine (physostigmine), (+)-epibatidine, and (+/-)-epibatidine, with Torpedo nicotin

91 ChRs, which is 26 times greater than that of epibatidine, and a alphabeta/alpha(7) K(i) ratio of 14,0

92 beta4 subunits with 1/1000th the affinity of epibatidine, and exhibits 1/60th and 1/190th the affinit

93 ty for the halpha4beta2 receptor relative to epibatidine, and like epibatidine, many exhibit robust a

94 rs, whereas nicotinoids such as nicotine and epibatidine are cationic and selective for mammalian sys

95 frontal affinity chromatography with [(3)H]-epibatidine as the marker ligand and epibatidine, nicoti

96 sing frontal chromatography with the agonist epibatidine as the marker.

97 (nAChR) subunit in complex with the agonist epibatidine at 3.2 A.

98 exhibits 1/60th and 1/190th the affinity of epibatidine at alpha7 and muscle-type nAChRs, respective

99 at equilibrium show that both enantiomers of epibatidine bind to adult and fetal receptors with shall

100 rtments and slowly released, blocking (125)I-epibatidine binding and desensitizing alpha4beta2Rs.

101 the gamma or the delta subunit and measured epibatidine binding and epibatidine-induced single-chann

102 We find that up-regulation of [(3)H]epibatidine binding and function in HEK293 cells stably

103 Receptor numbers were assessed by [(3)H]epibatidine binding and receptor function was measured b

104 centrations of nicotine (1 microM) increased epibatidine binding but functionally deactivated the nic

105 alpha4beta2 receptors, formed high affinity epibatidine binding complexes that are pentameric, traff

106 e nicotinic agonists in displacing (+/-)-[3H]epibatidine binding from spinal cord membranes correlate

107 HCl (A85380) showed a complete block of 125I-epibatidine binding in all regions investigated and did

108 ly, chronic nicotine produced an increase in epibatidine binding in several areas of the brain in bot

109 n control mice, long-term nicotine augmented epibatidine binding in several areas of the brain, inclu

110 gR transgenics, long-term nicotine increased epibatidine binding in some areas but not in the hippoca

111 In addition, we measured epibatidine binding in the brain and transcription statu

112 he caudate-putamen and had no effect on 125I-epibatidine binding in the frontal cortex or thalamus.

113 y significant abnormality was a reduction in epibatidine binding in the granule cell and Purkinje lay

114 earning and a significant increase in [(3)H] epibatidine binding in the hippocampus indicative of rec

115 "cytisine-resistant" sites), resolving [(3)H]epibatidine binding into three different populations, ea

116 [3H]Epibatidine binding is distinctly biphasic.

117 125I-Epibatidine binding sites are expressed throughout the c

118 antly, indicating that most up-regulated [3H]epibatidine binding sites are internal.

119 impermeant ligands indicated that 85% of [3H]epibatidine binding sites are intracellular.

120 We also show that the upregulation of epibatidine binding sites attributable to chronic nicoti

121 (K(i) < 3 nM) competed for a subset of [(3)H]epibatidine binding sites in mouse brain homogenates, bu

122 are previously uncharacterized high affinity epibatidine binding sites in the brain and indicate that

123 ecamylamine either failed to up-regulate [3H]epibatidine binding sites or up-regulated mildly at high

124 This reduction was confined to the [3H]epibatidine binding sites sensitive to inhibition by alp

125 Intracellular [3H]epibatidine binding sites were characterized after elimi

126 All agonists up-regulated [3H]epibatidine binding sites with EC50 values typically 10-

127 inds with high affinity at a subset of [(3)H]epibatidine binding sites with relatively low cytisine a

128 s classifications of the higher-affinity [3H]epibatidine binding sites.

129 w compounds has been carried out using [(3)H]epibatidine binding studies together with functional ass

130 In these studies [3H]epibatidine binding techniques were used to characterize

131 as a potent competitive inhibitor of (125)I-epibatidine binding to 5-HT(3)Rs.

132 Nicotine was a poor competitor for (125)I-epibatidine binding to 5-HT(3)Rs.

133 phenylbiguanide readily competed with (125)I-epibatidine binding to 5-HT(3)Rs.

134 ompetes with epibatidine, allowing for [(3)H]epibatidine binding to be used for structure-activity st

135 [(125)I]Epibatidine binding to brain membranes showed that the m

136 find that nicotine blocks only 75% of (125)I-epibatidine binding to rat brain membranes, whereas liga

137 rgic agents were used to define specific [3H]epibatidine binding to total (surface and intracellular)

138 nsity of nicotinic receptors measured by [3H]epibatidine binding was 7-fold higher in membranes from

139 mental retardation, although the lower [(3)H]epibatidine binding was apparent.

140 hibition studies showed that the decrease in epibatidine binding was due to loss of alpha-conotoxin M

141 In contrast, [3H]epibatidine binding was not detected from the extracellu

142 High-affinity epibatidine binding was present in the superficial dorsa

143 Kdapp values for [3H]epibatidine binding were 10 pM for alpha2beta2, 87 pM fo

144 evels of alpha3-independent -resistant [125I]epibatidine binding were also seen.

145 ces in nicotinic receptors assessed by [(3)H]epibatidine binding were significant and extensive (65%-

146 trol) exhibited a 55 to 60% decrease in 125I-epibatidine binding, which seemed to be due to a complet

147 of control) had a 40 to 50% decrease in 125I-epibatidine binding.

148 ts, but they fail to be detected using [(3)H]epibatidine binding.

149 ine dihydrochloride (A85380)-resistant [125I]epibatidine-binding nAChR subtypes, respectively.

150 In contrast, most -resistant [125I]epibatidine-binding nAChRs were dependent on alpha3 gene

151 lts show that more than three fourths of the epibatidine-binding receptors at both early and late emb

152 d alpha5 gene products coassemble to produce epibatidine-binding receptors.

153 ever, when receptors are fully desensitized, epibatidine binds in a biphasic manner, with dissociatio

154 of ligand docking simulations suggests that epibatidine binds in a single preferred orientation with

155 Because (i) epibatidine binds more tightly to the alpha gamma-bindin

156 of single-channel currents reveals that (-)-epibatidine binds with 15-fold selectivity to sites of a

157 (125)I-Epibatidine binds with a high affinity to native 5-HT(3)

158 ed activable state, the results suggest that epibatidine binds with unique site selectivity in activa

159 ificantly the antinociception induced by (+)-epibatidine but not (-)-epibatidine (12 microg/kg, s.c.)

160 The effect of (+)-epibatidine but not (-)-epibatidine was significantly in

161 line receptor (nAChR) agonists (nicotine and epibatidine), but also the alpha7 nAChR-selective antago

162 seizure sensitivity to the nicotinic agonist epibatidine, but not to the GABA(A) receptor blocker and

163 gand binding density as measured using [(3)H]epibatidine, but reduces the magnitude of up-regulation

164 gy conformer of 4A with (S)-nicotine and (-)-epibatidine can be achieved.

165 In contrast to epibatidine, carbamylcholine shows little site selectivi

166 H-SY5Y cells exhibited the high affinity for epibatidine characteristic of receptors formed from alph

167 muscarinic agonists chemically derived from epibatidine, CMI-936 and CMI-1145, displayed reduced ana

168 Homologous (epibatidine) competition experiments on total (surface a

169 Thus, the addition of the 3'-amino group to epibatidine confers potent antagonist activity to the co

170 tation responses elicited by intrathecal (-)-epibatidine, confirming a role for spinal excitatory ami

171 of alpha4beta2 nAChRs when measured with [3H]epibatidine, cytisine, nicotine, and acetylcholine.

172 HEK293 cells as measured by increased [(3)H]epibatidine density.

173 Repeated administration of (-)-epibatidine desensitized its responses as well as the ca

174 n assays and high affinity binding for [(3)H]epibatidine determined that all mutants retain functiona

175 h the Leu NH, but the potent nicotine analog epibatidine did not.

176 Comparison of [3H]epibatidine displacement in intact M10 cells and membran

177 high-affinity members of the series and (+)-epibatidine display a tight fit superposition of low-ene

178 tivity arises solely from different rates of epibatidine dissociation from the two sites.

179 ivo, ibogaine at 10 mg/kg completely blocked epibatidine-elicited antinociception in mice, a response

180 tane fragment of the potent nicotinic ligand epibatidine eliciting the greatest interaction energy of

181 to other nicotinic agonists, intrathecal (-)-epibatidine elicits dose-dependent increases in pressor,

182 acetylcholine receptors (nAChRs) labeled by epibatidine (Epb) in 11 brain areas.

183 iperzinium iodide (DMPP), cytisine (CYT) and epibatidine (EPI) were investigated on [3H]-norepinephri

184 .001 mg/kg of the nicotinic full agonist (+)-epibatidine ((+)-EPI).

185 ogy of a highly potent 18F-labeled analog of epibatidine, (+/-)-exo-2-(2-[18F]fluoro-5-pyridyl)-7-aza

186 tency for nicotinic agonists was as follows: epibatidine > nicotine = 3-(azetidinylmethoxy)pyridine (

187 over a 7000-fold range, with a rank order of epibatidine >> A85380 > cytisine approximately 1,1-dimet

188 igh-affinity, specific binding of 3H-labeled epibatidine (H-EBDN; macroscopic KD = 10 pM; kon = 0.74/

189 Epibatidine has been shown to be the most potent nicotin

190 tions, the prototypical nicotinic analgesic (epibatidine) has not yet been shown to modulate inhibito

191 In contrast to epibatidine, however, 5-iodo-A-85380 is more selective i

192 To compare the mode of binding of epibatidine in a muscle and a neuronal nAChR, we photola

193 e relate the binding properties of (+/-)-[3H]epibatidine in spinal cord membrane preparations to the

194 Intrathecal (-)-epibatidine, in addition to eliciting an initial and sub

195 te show similar site selectivity, we studied epibatidine-induced activation of mouse fetal and adult

196 K 8644) and calcium blockers on (+)- and (-)-epibatidine-induced antinociception was investigated in

197 ctional assays the lead compound antagonized epibatidine-induced Ca(2+) flux in alpha3beta4-transfect

198 ults established that bupropion (a) inhibits epibatidine-induced Ca(2+) influx in embryonic muscle AC

199 tions for Delta F agreed well with those for epibatidine-induced currents, but were shifted approxima

200 AT-1001 also potently and reversibly blocks epibatidine-induced inward currents in HEK cells transfe

201 subunit and measured epibatidine binding and epibatidine-induced single-channel currents.

202 Epibatidine inhibited serotonin-induced currents mediate

203 y blocking correlated waves of activity with epibatidine into both eyes.

204 Thus epibatidine is a potentially valuable probe of acetylcho

205 total synthesis of the natural product, (+)-epibatidine, is also provided.

206 Thus, epibatidine isomers pharmacological effect was different

207 Epibatidine itself was trapped; (125)I-epibatidine slow

208 termined by frontal chromatography for (+/-)-epibatidine (Kd: 0.27 +/- 0.05 nM) > A85380 (Kd: 17.2 +/

209 2 receptor relative to epibatidine, and like epibatidine, many exhibit robust analgesic efficacy in t

210 Thus, (+/-)-epibatidine may inhibit the vanilloid receptor in a mann

211 articular studies of analgesic properties of epibatidine, may need to be reinterpreted with respect t

212 sites in the central nervous system), (125)I-epibatidine (multiple sites), 5-[(125)I]iodo-3-[2(S)-aze

213 6Rb+ efflux assays indicate full efficacy of epibatidine, nicotine, and acetylcholine; partial effica

214 observed binding affinities for the agonists epibatidine, nicotine, and cytisine were consistent with

215 [(3)H]-epibatidine as the marker ligand and epibatidine, nicotine, and methyllycaconitine as the dis

216 Preinjection of blocking doses of unlabeled epibatidine, (-)-nicotine, lobeline and cytisine signifi

217 little effect on the binding affinities for epibatidine of receptors containing also alpha3 and beta

218 as alpha7nAChR agonists such as nicotine and epibatidine offered protection.

219 With measurements of [(1)(2)(5)I]-epibatidine or [(1)(2)(5)I]-bungarotoxin binding to nico

220 MII or inhibition of alpha-CtxMII binding by epibatidine or nicotine.

221 ther in vivo nAChR probes such as 3H-labeled epibatidine or norchloroepibatidine, [3H](-)-nicotine an

222 n a cation-pi interaction with TyrA, whereas epibatidine participates in a cation-pi interaction with

223 affinity-purified alpha4beta2 nAChRs, [(3)H]epibatidine photolabeled alpha4Tyr(195) (equivalent to T

224 a7-, or alpha3-selective agonists (GTS-21 or epibatidine, respectively).

225 sites with lower and higher affinity for [3H]epibatidine, respectively.

226 There was no significant blockade of the epibatidine response at 24 hr after the administration o

227 1-methyl-2-pyrrolidinyl)isoxazole, and (+/-)-epibatidine, resulted in concentration-dependent increas

228 -[3H]cytisine or (-)-[3H]nicotine, (+/-)-[3H]epibatidine reveals two sites; the ratio of high affinit

229 To determine the structural basis for epibatidine selectivity, we introduced mutations into ei

230 at desensitized muscle nicotinic receptors, epibatidine selects by 300-fold between the two agonist

231 the [(3)H]nicotine-, compared with the [(3)H]epibatidine-sensitive nAChR.

232 it is possible that (-)-1 is acting at a non-epibatidine-sensitive receptor subtype to antagonize nic

233 olved three times in poison frogs, decreased epibatidine sensitivity but at a cost of acetylcholine s

234 Epibatidine shares a highly conserved binding site with

235 alphadelta interface forms the low affinity epibatidine site, whereas the alphagamma and alphaepsilo

236 dopaminergic neurons, in contrast to (125)I-epibatidine sites.

237 Epibatidine itself was trapped; (125)I-epibatidine slow release from acidic vesicles was direct

238 between epibatidine and carbamylcholine; for epibatidine the rank order of affinities is alphaepsilon

239 The nicotinic receptor binding the agonist epibatidine (the high affinity receptor subtype, consist

240 n perturbing postnatal retinal activity with epibatidine, the ipsilateral projection fragments and th

241 2 subunits in the M10 cell line by using [3H]epibatidine to measure nAChR in cells in situ and in mem

242 and 4 inhibited the in vitro binding of [3H]epibatidine to nAChRs to a similar degree, with affiniti

243 of less than one in competing with (+/-)-[3H]epibatidine to spinal cord membranes indicating their in

244 agonists-acetylcholine (ACh), nicotine, and epibatidine-to the nicotinic acetylcholine receptor has

245 ious agonists methylcarbamylcholine or (+/-)-epibatidine together with nicotine resulted in less up-r

246 Nicotine exposure increased epibatidine trapping by increasing the numbers of acidic

247 rol conditions and is further impaired after epibatidine treatment.

248 uggested several different binding modes for epibatidine, varenicline, and 5a-g.

249 ptor binding sites measured with (+/-)-[(3)H]epibatidine was increased during the chronic treatment w

250 Epibatidine was more efficacious than ACh at LS receptor

251 The effect of (+)-epibatidine but not (-)-epibatidine was significantly increased by BAY K 8644 pr

252 Arecolone, (+)-epibatidine, and (+/-)-epibatidine were agonists with activation constants of 3

253 fects of the nicotinic agonists nicotine and epibatidine were blocked.

254 Two subtypes of receptors labeled by [3H]epibatidine were found: one that was increased about 4-f

255 ta4 receptor subtype, which binds (+/-)- [3H]epibatidine with a Kd value of 304+/-16 pM and a Bmax va

256 a and mutant delta(S36K+I178F) subunits bind epibatidine with decreased affinity compared to alphadel

257 a and mutant gamma(K34S+F172I) subunits bind epibatidine with increased affinity compared to alphagam

258 (physostigmine), (+)-epibatidine, and (+/-)-epibatidine, with Torpedo nicotinic acetylcholine recept