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Rosa J, de Carvalho Myskiw J, Fiorenza NG, Furini CRG, Sapiras GG, Izquierdo I. Hippocampal cholinergic receptors and the mTOR participation in fear-motivated inhibitory avoidance extinction memory. Behav Brain Res 2023; 437:114129. [PMID: 36179804 DOI: 10.1016/j.bbr.2022.114129] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 09/07/2022] [Accepted: 09/24/2022] [Indexed: 10/14/2022]
Abstract
Evidence has demonstrated the hippocampal cholinergic system and the mammalian target of rapamycin (mTOR) participation during the memory formation of aversive events. This study assessed the role of these systems in the hippocampus for the extinction memory process by submitting male Wistar rats to fear-motivated step-down inhibitory avoidance (IA). The post-extinction session administration of the nicotinic and muscarinic cholinergic receptor antagonists, mecamylamine and scopolamine, respectively, both at doses of 2 µg/µl/side, and rapamycin, an mTOR inhibitor (0.02 µg/µl/side), into the CA1 region of the dorsal hippocampus, impaired the IA extinction memory. Furthermore, the nicotinic and muscarinic cholinergic receptor agonists, nicotine and muscarine, respectively, had a dose-dependent effect on the IA extinction memory when administered intra-CA1, immediately after the extinction session. Nicotine (0.6 µg/µl/side) and muscarine (0.02 µg/µl/side), respectively, had no effect, while the higher doses (6 and 2 µg/µl/side, respectively) impaired the IA extinction memory. Interestingly, the co-administration of muscarine at the lower dose blocked the impairment that was induced by rapamycin. This effect was not observed when nicotine at the lower dose was co-administered. These results have demonstrated the participation of the cholinergic receptors and mTOR in the hippocampus for IA extinction, and that the cholinergic agonists had a dose-dependent effect on the IA extinction memory. This study provides insights related to the behavioural aspects and the neurobiological properties underlying the early stage of fear-motivated IA extinction memory consolidation and suggests that there is hippocampal muscarinic receptor participation independent of mTOR in this memory process.
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Affiliation(s)
- Jessica Rosa
- Memory Center, Brain Institute of Rio Grande do Sul, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Ipiranga 6690, Floor 2, 90610-600 Porto Alegre, RS, Brazil; Department of Pharmacology, School of Medicine of Ribeirao Preto, University of Sao Paulo (USP), Bandeirantes 3900, 14049-900 Ribeirao Preto, SP, Brazil.
| | - Jociane de Carvalho Myskiw
- Memory Center, Brain Institute of Rio Grande do Sul, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Ipiranga 6690, Floor 2, 90610-600 Porto Alegre, RS, Brazil; National Institute of Translational Neuroscience (INNT), National Research Council of Brazil, Federal University of Rio de Janeiro, 21941-902 Rio de Janeiro, RJ, Brazil; Department of Biophysics, Institute of Biosciences, Federal University of Rio Grande do Sul (UFRGS), Bento Gonçalves 9500, Building 43422, Room 208 A, 91501-970 Porto Alegre, RS, Brazil
| | - Natalia Gindri Fiorenza
- Memory Center, Brain Institute of Rio Grande do Sul, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Ipiranga 6690, Floor 2, 90610-600 Porto Alegre, RS, Brazil; Oswaldo Cruz Foundation (FIOCRUZ), Branch Ceara, 60760-000 Eusebio, CE, Brazil
| | - Cristiane Regina Guerino Furini
- Memory Center, Brain Institute of Rio Grande do Sul, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Ipiranga 6690, Floor 2, 90610-600 Porto Alegre, RS, Brazil; National Institute of Translational Neuroscience (INNT), National Research Council of Brazil, Federal University of Rio de Janeiro, 21941-902 Rio de Janeiro, RJ, Brazil; Laboratory of Cognition and Memory Neurobiology, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Ipiranga 6690, 3rd Floor, 90610-000 Porto Alegre, RS, Brazil
| | - Gerson Guilherme Sapiras
- Memory Center, Brain Institute of Rio Grande do Sul, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Ipiranga 6690, Floor 2, 90610-600 Porto Alegre, RS, Brazil; Clinical Hospital of Passo Fundo (HCPF), Tiradentes 295, 99010-260 Passo Fundo, RS, Brazil
| | - Ivan Izquierdo
- Memory Center, Brain Institute of Rio Grande do Sul, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Ipiranga 6690, Floor 2, 90610-600 Porto Alegre, RS, Brazil; National Institute of Translational Neuroscience (INNT), National Research Council of Brazil, Federal University of Rio de Janeiro, 21941-902 Rio de Janeiro, RJ, Brazil
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Neonicotinoids act like endocrine disrupting chemicals in newly-emerged bees and winter bees. Sci Rep 2017; 7:10979. [PMID: 28887455 PMCID: PMC5591280 DOI: 10.1038/s41598-017-10489-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 07/12/2017] [Indexed: 11/12/2022] Open
Abstract
Accumulating evidence suggests that neonicotinoids may have long-term adverse effects on bee health, yet our understanding of how this could occur is incomplete. Pesticides can act as endocrine disrupting chemicals (EDCs) in animals providing characteristic multiphasic dose-response curves and non-lethal endpoints in toxicity studies. However, it is not known if neonicotinoids act as EDCs in bees. To address this issue, we performed oral acute and chronic toxicity studies including concentrations recorded in nectar and pollen, applying acetamiprid, clothianidin, imidacloprid, and thiamethoxam to bumble bees, honey bees and leafcutter bees, the three most common bee species managed for pollination. In acute toxicity studies, late-onset symptoms, such as ataxia, were recorded as non-lethal endpoints for all three bee species. Clothianidin and thiamethoxam produced biphasic dose-response curves for all three bee species. Clothianidin and thiamethoxam were extremely toxic to winter worker honey bees prior to brood production in spring, making this the most sensitive bee stage identified to date. Chronic exposure to field-realistic levels of neonicotinoids reduced bee survival and caused significant late-onset symptoms for all three bee species. Given these findings, neonicotinoid risk should be reevaluated to address the EDC-like behavior and the sensitivity of winter worker honey bees.
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Cai Q, Turner BD, Sheng D, Sloan S. The kinetics of fluoride sorption by zeolite: Effects of cadmium, barium and manganese. JOURNAL OF CONTAMINANT HYDROLOGY 2015; 177-178:136-147. [PMID: 25909159 DOI: 10.1016/j.jconhyd.2015.03.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 03/17/2015] [Accepted: 03/18/2015] [Indexed: 06/04/2023]
Abstract
Industrial wastewaters often consist of a complex chemical cocktail with treatment of target contaminants complicated by adverse chemical reactions. The impact of metal ions (Cd(2+), Ba(2+) and Mn(2+)) on the kinetics of fluoride removal from solution by natural zeolite was investigated. In order to better understand the kinetics, the pseudo-second order (PSO), Hill (Hill 4 and Hill 5) and intra-particle diffusion (IPD) models were applied. Model fitting was compared using the Akaike Information Criterion (AIC) and the Schwarz Bayesian Information Criterion (BIC). The Hill models (Hill 4 and Hill 5) were found to be superior in describing the fluoride removal processes due to the sigmoidal nature of the kinetics. Results indicate that the presence of Mn (100 mg L(-1)) and Cd (100 mg L(-1)) respectively increases the rate of fluoride sorption by a factor of ~28.3 and ~10.9, the maximum sorption capacity is increased by ~2.2 and ~1.7. The presence of Ba (100 mg L(-1)) initially inhibited fluoride removal and very poor fits were obtained for all models. Fitting was best described with a biphasic sigmoidal model with the degree of inhibition decreasing with increasing temperature suggesting that at least two processes are involved with fluoride sorption onto natural zeolite in the presence of Ba.
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Affiliation(s)
- Qianqian Cai
- Centre of Excellence for Geotechnical Science and Engineering, Civil Surveying and Environmental Engineering, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia.
| | - Brett D Turner
- Centre of Excellence for Geotechnical Science and Engineering, Civil Surveying and Environmental Engineering, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia.
| | - Daichao Sheng
- Centre of Excellence for Geotechnical Science and Engineering, Civil Surveying and Environmental Engineering, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia.
| | - Scott Sloan
- Centre of Excellence for Geotechnical Science and Engineering, Civil Surveying and Environmental Engineering, The University of Newcastle, University Drive, Callaghan, NSW 2308, Australia.
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Arnt J, Lembøl HL, Meier E, Pedersen H. Discriminative stimulus properties of the muscarinic receptor agonists Lu 26-046 and O-Me-THPO in rats: evidence for involvement of different muscarinic receptor subtypes. Eur J Pharmacol 1992; 218:159-69. [PMID: 1397027 DOI: 10.1016/0014-2999(92)90160-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The discriminative cues induced by the muscarinic receptor agonists Lu 26-046 ((-)-7-methyl-3(2-propynyloxy)-4,5,6,7-tetrahydroisothiazolo [4,5-c]pyridine ) and O-Me-THPO (3-methoxy-4,5,6,7-tetrahydroisoxazolo[4,5-c]pyridine) were investigated. The results were compared with those obtained for the binding profiles of these agonists at central muscarinic receptors and with results concerning their functional effects at peripheral muscarinic receptors in vitro. Lu 26-046 had preferential affinity for M1 versus M2 receptors (Ki index [3H]quinuclidinyl benzilate ([3H]QNB/[3H]pirenzepine 4.2) and had partial agonistic activity at M1 and M2 receptors in rat superior cervical ganglion and guinea pig left atrim, respectively. A weak antagonistic effect at M3 receptors in guinea pig ileum was observed. O-Me-THPO had non-selective agonistic effects at peripheral M1, M2 and M3 receptors and had a slight preference for central M2 receptors in binding experiments (M2/M1 index 0.31). Lu 26-046 dose dependently substituted for Lu 26-046 and partially substituted for O-Me-THPO in rats trained to discriminate Lu 26-046 and O-Me-THPO from saline, respectively. The (+)-enantiomer of Lu 26-046, Lu 26-047, had weak partial M1 agonistic activity and M2/M3 antagonistic effects at peripheral receptors. Lu 26-047 also had a high M2/M1 index (9.3) in binding experiments. Lu 26-047 substituted for Lu 26-046, but preferentially inhibited the effect of O-Me-THPO. Pilocarpine had a preferential effect in Lu 26-046-trained rats, while oxotremorine and arecoline had preferential effects in O-Me-THPO-trained rats. Large increases in latency times or a disruption of responding was generally observed. These compounds were full agonists at peripheral M1, M2 and M3 receptors. The muscarinic receptor antagonist scopolamine antagonized the effect of O-Me-THPO and partially inhibited the effect of Lu 26-046. Scopolamine partially substituted for Lu 26-046. The quaternary muscarinic receptor agonist N-methyl atropine had no effect, indicating that the cues are mediated by central muscarinic receptors. It is suggested that the discriminative cues of Lu 26-046 and O-Me-THPO are preferentially mediated by central M1 (partial) and M2 receptor stimulation, respectively. The role of central M3 receptors is not known.
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Affiliation(s)
- J Arnt
- Research laboratories, H. Lundbeck A/S, Copenhagen, Denmark
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Boddeke HW, Buttini M. Pharmacological properties of cloned muscarinic receptors expressed in A9 L cells; comparison with in vitro models. Eur J Pharmacol 1991; 202:151-7. [PMID: 1802743 DOI: 10.1016/0014-2999(91)90289-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The effects of a series of muscarinic agonists and antagonists at cloned m1 and m3 muscarinic receptors expressed in mouse fibroblast A9 L cells have been compared with their effects in in vitro models of M1 (rat superior cervical ganglion) and M3 (guinea-pig ileum) muscarinic receptors. A good correlation existed between the potencies of muscarinic agonists at cloned m1 muscarinic receptors and the M1 sites in rat ganglion (r = 0.80) as well as at cloned m3 receptors and guinea-pig ileum M3 receptors (r = 0.87). However, cross correlations of potencies in rat ganglion and cloned m3 receptors as well as in guinea-pig ileum and in cloned m1 receptors also yielded relatively high correlation coefficients (0.71 and 0.91, respectively). Low correlation coefficients were found for the maximal responses of muscarinic agonists in rat ganglion and cloned m1 receptors (0.53) and in guinea-pig ileum and cloned m3 receptors (0.36). A high correlation between pA2 values of muscarinic antagonists at cloned m1 receptors and in rat ganglion (r = 0.97) and between cloned m3 receptors and guinea-pig ileum (r = 0.98) was found. Cross correlation of pA2 values in rat ganglion and cloned m3 receptors and in guinea-pig ileum and cloned m1 receptors yielded correlation coefficients of 0.82 and 0.72, respectively. The data indicate that the cloned muscarinic receptor sites seem similar to the corresponding endogenous sites. The good correlations in corresponding but also non-corresponding receptor models reflect the relatively low selectivity of the majority of the compounds investigated.
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Affiliation(s)
- H W Boddeke
- Preclinical Research, Sandoz Pharma Ltd., Basle, Switzerland
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Freedman SB, Harley EA, Patel S, Newberry NR, Gilbert MJ, McKnight AT, Tang JK, Maguire JJ, Mudunkotuwa NT, Baker R. A novel series of non-quaternary oxadiazoles acting as full agonists at muscarinic receptors. Br J Pharmacol 1990; 101:575-80. [PMID: 2076477 PMCID: PMC1917727 DOI: 10.1111/j.1476-5381.1990.tb14123.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
1 A novel series of non-quaternary oxadiazole-based muscarinic agonists demonstrated high affinity for muscarinic receptors. 2. These agonists possessed high efficacy in the nanomolar range at muscarinic receptors in the superior cervical ganglion, atrium and ileum but did not show selectivity across the tissue preparations. 3. Two amino oxadiazoles, one from a quinuclidine series (L-660,863) and one from a 1-azanorbornane series (L-670,207) possessed a high ratio of potency for displacing the binding of [3H]-N-methyl-scopolamine ([3H]-NMS) to potency for displacing the agonist [3H]-oxotremorine-M cortex. 4. The two azanorbornane derivatives L-670,548 and L-670,207 stimulated the turnover of phosphatidylinositol in the cortex with a potency higher than that obtained with any other known muscarinic agonist (ED50 0.26 and 0.18 microM respectively). 5. The maximum response obtained with L-670,207 was greater than that observed for carbachol but was comparable to that of the natural ligand acetylcholine. 6. These oxadiazole muscarinic agonists are among the most potent and efficacious non-quaternary muscarinic agonists ever described.
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Affiliation(s)
- S B Freedman
- Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Harlow, Essex
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Roberts KE, Newberry NR. A pharmacological study of the responses induced by muscarinic agonists on the isolated superior cervical ganglion of the guinea-pig. Eur J Pharmacol 1990; 186:257-65. [PMID: 2289527 DOI: 10.1016/0014-2999(90)90441-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We have studied the muscarinic agonist induced responses on the guinea-pig superior cervical ganglion in vitro, as recorded from the internal carotid nerve using a grease-gap. The principal response was a depolarization, but a small hyperpolarizing response could be revealed under certain conditions. We determined the pA2 of a number of muscarinic antagonists against the muscarine induced depolarization. Four selective antagonists and atropine appeared to act competitively. The rank order of their pA2s was 4-DAMP (8.5), atropine (8.4), pirenzepine (8.0), methoctramine (7.2) and AF-DX 116 (6.3). In addition to muscarine, we assessed the potency and relative maximum response of nine other muscarinic compounds to depolarize this preparation: carbachol, 5-methylfurmethide, oxotremorine, oxotremorine-M, pilocarpine, RS 86, AF102B and two novel compounds L-670548 and L-679512. L-670548 was the most potent and AF102B was the least potent agonist tested. Only AF102B evoked a maximum depolarization that was significantly smaller than muscarine. A hyperpolarizing response to carbachol (1 microM) could be recorded when the superfusing medium contained 0.3 microM pirenzepine and only 0.1 mM CaCl2 (cf. usual 2.5 mM). This response was relatively small compared to that evoked on the superior cervical ganglion of the rat. It was blocked by the cardioselective antagonists methoctramine (0.1-0.3 microM) and AF-DX 116 (0.3-1.0 microM). Of the 10 agonists tested, only carbachol, oxotremorine and oxotremorine-M reproducibly evoked a hyperpolarizing response. It was concluded that muscarinic agonists can induce a depolarization of the guinea-pig superior cervical ganglion mediated by M1 receptors. The activation of cardiac-like M2 receptors resulted in a hyperpolarizing response that was relatively small.
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Affiliation(s)
- K E Roberts
- Merck, Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Harlow, Essex, U.K
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Choo LK, Mitchelson F. Selective inhibition of responses to carbachol and McN-A-343 in the rabbit vas deferens. Clin Exp Pharmacol Physiol 1990; 17:601-11. [PMID: 1703935 DOI: 10.1111/j.1440-1681.1990.tb01361.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
1. The effect of several selective muscarine receptor antagonists were evaluated on the responses of carbachol (CCh) and McN-A-343 (McN) during sympathetic nerve stimulation in the rabbit vas deferens. 2. The muscarine M1 receptor antagonist pirenzepine exhibited similar apparent pKB values for antagonism of the prejunctional inhibitory response of either CCh (pKB, 8.2) or McN (pKB, 8.5) on sympathetic nerve stimulation. 3. The muscarine M2 receptor antagonists, pancuronium and the bisalkyl ammonium compound 'C7/3-phth' were selective inhibitors of the postjunctional facilitatory response produced by CCh on sympathetic nerve stimulation. They were also 17- and three-fold, respectively, less potent against the inhibitory responses of McN on sympathetic nerve stimulation. The apparent pKB value of pancuronium on the inhibitory response produced by CCh did not differ significantly (P greater than 0.05) from that using McN. A similar finding was made for C7/3-phth. 4. Selective blockade of the inhibitory response to CCh with pirenzepine (0.03 or 0.5 mumol/L) did not significantly (P greater than 0.05) modify the apparent pKB value for pancuronium on the facilitatory response of CCh. 5. Selective blockade of the facilitatory response to CCh with a low concentration of pancuronium (0.5 mumol/L) did not significantly (P greater than 0.05) modify the apparent pKB value for pancuronium (30 mumol/L) on the inhibitory response of CCh. 6. It is suggested that CCh and McN activate the same prejunctional M1 muscarine receptor and that pancuronium is the most selective of the muscarine M2 receptor antagonists presently tested in this preparation for distinguishing between muscarine M1 and M2 receptors.
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Affiliation(s)
- L K Choo
- School of Pharmacology, Victorian College of Pharmacy, Parkville, Australia
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Newberry NR, Gilbert MJ. Pertussis toxin sensitivity of drug-induced potentials on the rat superior cervical ganglion. Eur J Pharmacol 1989; 163:245-52. [PMID: 2721573 DOI: 10.1016/0014-2999(89)90193-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We have investigated the action of pertussis toxin on a range of receptor-mediated responses of the rat superior cervical ganglion in vitro. The ganglia were treated with pertussis toxin for 24 h at 37 degrees C using an in vitro method. Appropriate controls were also carried out. Pertussis toxin (1 microgram/ml) reduced ganglionic hyperpolarisations mediated by adenosine, alpha 2, 5-HT1A, M2 and GABAB receptors. The GABAB-mediated hyperpolarisation of this preparation, evoked by baclofen and GABA in a bicuculline-resistant manner, has not previously been reported. Pertussis toxin did not reduce ganglionic depolarisations evoked by potassium chloride and 5-HT3, GABAA and nicotinic receptors. Depolarisations to muscarine and noradrenaline, probably mediated by M1 and beta-receptors, also appeared to be resistant to pertussis toxin. The similar sensitivity of the various ganglionic hyperpolarisations to pertussis toxin indicates that they may all be mediated by similar G-proteins.
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Affiliation(s)
- N R Newberry
- Merck Sharp & Dohme Research Laboratories, Neuroscience Research Centre, Harlow, Essex, U.K
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