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Morales L, Vallcaneras S, Delsouc MB, Filippa V, Aguilera-Merlo C, Fernández M, Casais M. Neuromodulatory effect of GnRH from coeliac ganglion on luteal regression in the late pregnant rat. Cell Tissue Res 2021; 384:487-498. [PMID: 33779845 DOI: 10.1007/s00441-021-03436-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 02/18/2021] [Indexed: 12/29/2022]
Abstract
The GnRH/GnRH receptor system has been found in several extrapituitary tissues, although its physiological significance has not yet been well established. Taking into account that the peripheral neural system can act as a modulator of pregnancy corpus luteum, the objective was to physiologically investigate the presence of the GnRH system in coeliac ganglion (CG) and to analyse its possible involvement in luteal regression through the superior ovarian nerve (SON) at the end of pregnancy in the rat. The integrated ex vivo CG-SON-Ovary system of rats on day 21 of pregnancy was used. Cetrorelix (CTX), a GnRH receptor antagonist, was added into the ganglionic compartment while the control systems were untreated. Ganglionic GnRH release was detected under basal conditions. Then, the CTX addition in CG increased it, which would indicate the blockade of the receptor. In turn, CTX in CG caused an increase in ovarian progesterone release. Furthermore, the luteal cells showed an increase in the expression of Hsd3b1 and a decrease in the expression of Akr1c3 (progesterone synthesis and degradation enzymes, respectively), reduced TUNEL staining according to an increase in the antioxidant defence system activity and low lipid peroxide levels. The ovarian and ganglionic nitric oxide (NO) release increased, while the luteal nitrotyrosine content, measured as nitrosative stress marker, decreased. CTX in CG decreased the ovarian noradrenaline release. The present study provides evidence that GnRH from CG may trigger neuronal signals that promote the luteal regression in late pregnancy by affecting the release of NO and noradrenaline in the ovary.
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Affiliation(s)
- Laura Morales
- Laboratorio de Biología de la Reproducción (LABIR), Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Instituto Multidisciplinario de Investigaciones Biológicas de San Luis (IMIBIO-SL-CONICET), Av. Ejército de los Andes 950, D5700HHW, San Luis, Argentina
| | - Sandra Vallcaneras
- Laboratorio de Biología de la Reproducción (LABIR), Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Instituto Multidisciplinario de Investigaciones Biológicas de San Luis (IMIBIO-SL-CONICET), Av. Ejército de los Andes 950, D5700HHW, San Luis, Argentina
| | - María Belén Delsouc
- Laboratorio de Biología de la Reproducción (LABIR), Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Instituto Multidisciplinario de Investigaciones Biológicas de San Luis (IMIBIO-SL-CONICET), Av. Ejército de los Andes 950, D5700HHW, San Luis, Argentina
| | - Verónica Filippa
- Histología, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Av. Ejército de los Andes 950, Bloque I, Piso No. 1, 5700, San Luis, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), 5700, San Luis, Argentina
| | - Claudia Aguilera-Merlo
- Histología, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Av. Ejército de los Andes 950, Bloque I, Piso No. 1, 5700, San Luis, Argentina
| | - Marina Fernández
- Instituto de Biología y Medicina Experimental (IBYME-CONICET), V. de Obligado 2490, C1428ADN, Buenos Aires, Argentina
| | - Marilina Casais
- Laboratorio de Biología de la Reproducción (LABIR), Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Instituto Multidisciplinario de Investigaciones Biológicas de San Luis (IMIBIO-SL-CONICET), Av. Ejército de los Andes 950, D5700HHW, San Luis, Argentina.
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Delsouc MB, Della Vedova MC, Ramírez D, Delgado SM, Casais M. The production of nitric oxide in the coeliac ganglion modulates the effect of cholinergic neurotransmission on the rat ovary during the preovulatory period. Nitric Oxide 2018; 75:85-94. [PMID: 29501650 DOI: 10.1016/j.niox.2018.02.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 02/07/2018] [Accepted: 02/28/2018] [Indexed: 01/29/2023]
Abstract
The aim of the present work was to investigate whether the nitric oxide produced by the nitric oxide/nitric oxide synthase (NO/NOS) system present in the coeliac ganglion modulates the effects of cholinergic innervation on oxidative status, steroidogenesis and apoptotic mechanisms that take place in the rat ovary during the first proestrous. An ex vivo Coeliac Ganglion- Superior Ovarian Nerve- Ovary (CG-SON-O) system was used. Cholinergic stimulation of the CG was achieved by 10-6 M Acetylcholine (Ach). Furthermore, 400 μM Aminoguanidine (AG) - an inhibitor of inducible-NOS was added in the CG compartment in absence and presence of Ach. It was found that Ach in the CG compartment promotes apoptosis in ovarian tissue, probably due to the oxidative stress generated. AG in the CG compartment decreases the release of NO and progesterone, and increases the release of estradiol from the ovary. The CG co-treatment with Ach and AG counteracts the effects of the ganglionic cholinergic agonist on ovarian oxidative stress, increases hormone production and decreases Fas mRNA expression. These results suggest that NO is an endogenous modulator of cholinergic neurotransmission in CG, with implication in ovarian steroidogenesis and the apoptotic mechanisms that take place in the ovary during the preovulatory period in rats.
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Affiliation(s)
- María B Delsouc
- Laboratorio de Biología de la Reproducción (LABIR), Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina; Instituto Multidisciplinario de Investigaciones Biológicas de San Luis (IMIBIO-SL), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - María C Della Vedova
- Laboratorio de Medicina Experimental y Traduccional (LME&T), Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina; Instituto Multidisciplinario de Investigaciones Biológicas de San Luis (IMIBIO-SL), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Darío Ramírez
- Laboratorio de Medicina Experimental y Traduccional (LME&T), Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina; Instituto Multidisciplinario de Investigaciones Biológicas de San Luis (IMIBIO-SL), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Silvia M Delgado
- Laboratorio de Biología de la Reproducción (LABIR), Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina
| | - Marilina Casais
- Laboratorio de Biología de la Reproducción (LABIR), Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina; Instituto Multidisciplinario de Investigaciones Biológicas de San Luis (IMIBIO-SL), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
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3
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Delsouc MB, Morales LD, Vallcaneras SS, Bronzi D, Anzulovich AC, Delgado SM, Casais M. Participation of the extrinsic cholinergic innervation in the action of nitric oxide on the ovarian steroidogenesis in the first proestrous in rats. Gen Comp Endocrinol 2016; 236:54-62. [PMID: 27388663 DOI: 10.1016/j.ygcen.2016.07.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 06/28/2016] [Accepted: 07/03/2016] [Indexed: 11/21/2022]
Abstract
An ex-vivo Coeliac Ganglion-Superior Ovarian Nerve-Ovary (CG-SON-O) system and an ovary without peripheral neural influence from virgin rats in the first proestrous were used to test whether ovarian extrinsic innervation and nitric oxide (NO) affects steroidogenesis in the ovary. The CG and the ovary were placed in separate buffered-compartments, connected by the SON. Stimulation of the CG was achieved by 10(-6)M acetylcholine (Ach). The ovary without peripheral neural influence was placed alone in a buffered-compartment. To test a possible role of NO in the ovarian response to peripheral neural influence, 100μM sodium nitroprusside (SNP, an NO donor) and 100μM N(G)-nitro-l-arginine methyl ester (l-NAME, an inhibitor of NO synthase) were added to the ovarian compartment separately. In the CG-SON-O system, SNP into the ovarian compartment increased the concentration of NO, reduced the release of progesterone and increased the release of estradiol (E2), increasing the mRNAs related to their synthesis enzyme. The addition of l-NAME to the ovarian compartment caused an opposite effect. In the ovary alone, NO manifested an antisteroidogenic effect on both hormones. These results show that the ovarian extrinsic innervation maintains a direct relationship between NO and E2, both needed at high levels during the follicular phase, allowing the continuity of the estrous cycle.
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Affiliation(s)
- María B Delsouc
- Laboratorio de Biología de la Reproducción (LABIR), Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina; Instituto Multidisciplinario de Investigaciones Biológicas de San Luis (IMIBIO-SL), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
| | - Laura D Morales
- Laboratorio de Biología de la Reproducción (LABIR), Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina; Instituto Multidisciplinario de Investigaciones Biológicas de San Luis (IMIBIO-SL), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Sandra S Vallcaneras
- Laboratorio de Biología de la Reproducción (LABIR), Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina; Instituto Multidisciplinario de Investigaciones Biológicas de San Luis (IMIBIO-SL), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Daniela Bronzi
- Laboratorio de Biología de la Reproducción (LABIR), Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina; Instituto Multidisciplinario de Investigaciones Biológicas de San Luis (IMIBIO-SL), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Ana C Anzulovich
- Laboratorio de Cronobiología (LABCRON), Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina; Instituto Multidisciplinario de Investigaciones Biológicas de San Luis (IMIBIO-SL), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - Silvia M Delgado
- Laboratorio de Biología de la Reproducción (LABIR), Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina; Laboratorio de Cronobiología (LABCRON), Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina
| | - Marilina Casais
- Laboratorio de Biología de la Reproducción (LABIR), Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, San Luis, Argentina; Instituto Multidisciplinario de Investigaciones Biológicas de San Luis (IMIBIO-SL), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
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4
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Lanzafame AA, Christopoulos A, Mitchelson F. Cellular Signaling Mechanisms for Muscarinic Acetylcholine Receptors. ACTA ACUST UNITED AC 2011. [DOI: 10.3109/10606820308263] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Fasano C, Niel JP. The mammalian sympathetic prevertebral ganglia: Models for the study of neuronal networks and basic neuronal properties. Auton Neurosci 2009; 150:8-20. [DOI: 10.1016/j.autneu.2009.06.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Revised: 06/04/2009] [Accepted: 06/05/2009] [Indexed: 11/24/2022]
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Mills K, Chess-Williams R. Pharmacology of the internal anal sphincter and its relevance to faecal incontinence. ACTA ACUST UNITED AC 2009; 29:85-95. [PMID: 19566748 DOI: 10.1111/j.1474-8673.2009.00437.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
1 The internal anal sphincter (IAS) has a spontaneous tone and is the main contributor to the maintenance of faecal continence. The spontaneous resting tone exhibited by the sphincter can be modified by neurotransmitters from the autonomic and enteric nervous systems. 2 In this review, the influence of the sympathetic and parasympathetic nervous systems on IAS tone are discussed and the putative roles of nitric oxide, carbon monoxide, vasoactive intestinal peptide and adenosine triphosphate in non-adrenergic non-cholinergic transmission are considered. 3 Faecal incontinence is a common condition that places a heavy financial burden on the health service and severely affects patients' quality of life. Resting anal pressure is reduced in patients with faecal incontinence and agents that increase sphincter tone tend to relieve symptoms. The results of clinical studies of the use of phenylephrine to treat faecal incontinence are reviewed. 4 It is concluded that the IAS is a potential target for drug development for the treatment of faecal incontinence.
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Affiliation(s)
- K Mills
- Faculty of Health Sciences & Medicine, Bond University, Queensland 4229, Australia
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Ercoli J, Miolan JP, Niel JP, Quinson N. Presynaptic GABA-A receptors prevent depression of nicotinic transmission in rabbit coeliac ganglion neurones. Eur J Neurosci 2007; 25:1307-18. [PMID: 17425557 DOI: 10.1111/j.1460-9568.2007.05382.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We investigated the involvement of GABA-A receptors in the modulation of the nicotinic transmission of central origin in isolated rabbit coeliac ganglia. Our study was performed in vitro and the electrical activity of the ganglionic neurones was recorded using intracellular recording techniques. During iterative stimulation of the splanchnic nerves, the synaptic action potential probability decreased gradually, indicating a depression of the nicotinic activation. Pharmacological agents acting at GABA-A receptors modulated the action potential probability during the train of pulses. Muscimol (a GABA-A receptor agonist), diazepam (a benzodiazepine site agonist) and 1-[2-[[(diphenylmethylene)imino]oxy]ethyl]-1,2,5,6-tetrahydro-3-pyridinecarboxylic acid hydrochloride (a GABA uptake blocker) increased this probability. Conversely, gabazine or bicuculline (two GABA-A receptor antagonists), picrotoxin (a picrotoxin site agonist) and flumazenil (a benzodiazepine site antagonist) reduced it. These results demonstrate that endogenous GABA, released during the train of pulses, facilitates the central nicotinic activation of the ganglionic neurones by acting on GABA-A receptors. Muscimol also reduced the amplitude ratio of excitatory postsynaptic potentials triggered during the paired-pulse protocol without any change in postsynaptic properties. This result is consistent with a presynaptic action of GABA-A receptors. Our study shows that presynaptic GABA-A receptors facilitate the central nicotinic activation of prevertebral ganglionic neurones and thus play a novel role in the integrative properties of the sympathetic prevertebral ganglia.
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Affiliation(s)
- Jennifer Ercoli
- Laboratoire de Physiologie Neurovégétative, UMR Université Paul Cézanne Aix-Marseille III-CNRS-INRA, Faculté des Sciences et Techniques, 13397 Marseille cedex 20, France
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8
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Lau YE, Galligan JJ, Kreulen DL, Fink GD. Activation of ETB receptors increases superoxide levels in sympathetic ganglia in vivo. Am J Physiol Regul Integr Comp Physiol 2005; 290:R90-5. [PMID: 16179487 DOI: 10.1152/ajpregu.00505.2005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Dai and colleagues (Dai X, Galligan JJ, Watts SW, Fink GD, and Kreulen DL. Hypertension 43: 1048-1054, 2004) found that endothelin (ET) stimulated O2- production in sympathetic ganglion neurons in vitro by activating ET(B) receptors. The objective of the present study was to determine whether activation of ET(B) receptors in vivo elevates O2- levels in sympathetic ganglia. Because ET(B) receptor activation increases blood pressure, we also sought to determine whether alteration in O2- levels was a direct effect of ET(B) receptor activation on sympathetic ganglia or an indirect consequence of hypertension. Male Sprague-Dawley rats received intravenous infusions of either the specific ET(B) receptor agonist sarafotoxin 6c (S6c; 5 pmol.kg(-1).min(-1)) or isotonic saline at 0.01 ml/min (control) for 120 min. To measure O2- levels, we removed the inferior mesenteric ganglion immediately after infusion and stained it with dihydroethidine (DHE). Mean arterial pressure increased 26.6 +/- 1.7 mmHg in the S6c-treated rats and 3.65 +/- 6 mmHg in control rats. Measurements of average pixel intensity revealed that the DHE fluorescence in ganglionic neurons and surrounding glial cells were 96.7% and 160% greater in S6c-treated than in control rats, respectively. To evaluate the effect of elevated blood pressure on O2- production, a separate group of rats received phenylephrine (PE; 10 mug.kg(-1).min(-1) iv) for 2 h. MAP increased 31 +/- 1.2 mmHg in PE-infused rats. The DHE fluorescence intensity in ganglia of PE-infused rats was significantly greater than that of control rats, 137.7% in neurons and 104.6% in glia but significantly lower than in ganglia from S6c rats. We conclude that ET(B) receptor activation in vivo significantly enhances O2- levels in sympathetic ganglia, due to both pressor effects and direct stimulation of ET(B) receptors in ganglion cells.
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Affiliation(s)
- Yanny E Lau
- Department of Pharmacology/Toxicology, B327 Life Science, Michigan State University, East Lansing, MI 48824, USA
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Yin X, Cui W, Hu G, Wang H. Desensitization of α7 nicotinic receptors potentiated the inhibitory effect on M-current induced by stimulation of muscarinic receptors in rat superior cervical ganglion neurons. J Neural Transm (Vienna) 2004; 112:1133-48. [PMID: 15622441 DOI: 10.1007/s00702-004-0260-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2004] [Accepted: 11/07/2004] [Indexed: 10/26/2022]
Abstract
Whole-cell patch-clamp recording from rat superior cervical ganglion neurons in culture was used to investigate the modulatory effect of desensitized alpha7-nAChRs on mAChRs. An inward alpha-bungarotoxin and methyllycaconitine sensitive current was elicited by rapid application of choline, which consisted of a fast and a slow desensitizing component. The amplitude of choline-evoked currents recorded 0.5, 1, 2, and 3 min after the prolonged application of choline (10 mM, 30 s) decreased to 25.3 +/- 9.2%, 45.9 +/- 11.8%, 66.3 +/- 14.5%, and 73.9 +/- 13.3% of their baseline levels, respectively. The amplitudes of M-currents, recorded at the same time intervals after the similar prolonged stimulation with choline, were decreased to 52.7 +/- 17.4%, 63.9 +/- 4.2%, 70.9 +/- 2.8%, and 72.9 +/- 17.3% of initial values respectively by focal application of pilocarpine (1 mM, 5 s) onto the soma of neurons. By contrast, before the desensitization of alpha7-nAChRs, M-currents were only decreased to 79.8 +/- 13.7% of baseline levels by pilocarpine (1 mM, 5 s). Whereas the desensitization of alpha7-nAChRs had no direct effects on M-currents, and the facilitated effects on muscarinic agonists on the M-currents induced by desensitized alpha7-nAChRs, were removed in the presence of alpha-bungarotoxin and methyllycaconitine. These results indicated that desensitization of alpha7-nAChRs could potentiate the inhibitory effect on M-current by stimulation of mAChRs with their agonist.
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Affiliation(s)
- X Yin
- Beijing Institute of Pharmacology and Toxicology, Beijing, China
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10
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Werry TD, Wilkinson GF, Willars GB. Mechanisms of cross-talk between G-protein-coupled receptors resulting in enhanced release of intracellular Ca2+. Biochem J 2003; 374:281-96. [PMID: 12790797 PMCID: PMC1223610 DOI: 10.1042/bj20030312] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2003] [Revised: 06/03/2003] [Accepted: 06/05/2003] [Indexed: 12/21/2022]
Abstract
Alteration in [Ca(2+)](i) (the intracellular concentration of Ca(2+)) is a key regulator of many cellular processes. To allow precise regulation of [Ca(2+)](i) and a diversity of signalling by this ion, cells possess many mechanisms by which they are able to control [Ca(2+)](i) both globally and at the subcellular level. Among these are many members of the superfamily of GPCRs (G-protein-coupled receptors), which are characterized by the presence of seven transmembrane domains. Typically, those receptors able to activate PLC (phospholipase C) enzymes cause release of Ca(2+) from intracellular stores and influence Ca(2+) entry across the plasma membrane. It has been well documented that Ca(2+) signalling by one type of GPCR can be influenced by stimulation of a different type of GPCR. Indeed, many studies have demonstrated heterologous desensitization between two different PLC-coupled GPCRs. This is not surprising, given our current understanding of negative-feedback regulation and the likely shared components of the signalling pathway. However, there are also many documented examples of interactions between GPCRs, often coupling preferentially to different signalling pathways, which result in a potentiation of Ca(2+) signalling. Such interactions have important implications for both the control of cell function and the interpretation of in vitro cell-based assays. However, there is currently no single mechanism that adequately accounts for all examples of this type of cross-talk. Indeed, many studies either have not addressed this issue or have been unable to determine the mechanism(s) involved. This review seeks to explore a range of possible mechanisms to convey their potential diversity and to provide a basis for further experimental investigation.
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Affiliation(s)
- Tim D Werry
- Department of Cell Physiology and Pharmacology, Medical Sciences Building, University of Leicester, UK
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11
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Fasano C, Miolan JP, Niel JP. Modulation by C2 ceramide of the nicotinic transmission within the coeliac ganglion in the rabbit. Neuroscience 2003; 116:753-9. [PMID: 12573717 DOI: 10.1016/s0306-4522(02)00760-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We have investigated the modulation by ceramide of the nicotinic activation of the prevertebral sympathetic neurons. Our study was performed in vitro in rabbit isolated coeliac ganglion, using intracellular recording techniques. We have used C(2) ceramide, a permeant analog of ceramide. The effects of C(2) ceramide were first assessed when nicotinic activation was elicited without modulatory mechanisms (fast excitatory postsynaptic potentials triggered by stimulation of the thoracic splanchnic nerves with a single pulse). In all the neurons tested, C(2) ceramide triggered an increase in the amplitude of the fast excitatory postsynaptic potentials demonstrating a direct facilitatory effect on the nicotinic activation. We then investigated the effects of C(2) ceramide on modulatory mechanisms of this activation. These mechanisms occur when a train of pulses of supramaximum intensity is applied on the splanchnic nerves. During the train, a gradual depression of fast nicotinic activation occurred: the pulses failed to systematically elicit action potentials. We have previously demonstrated that this regulatory phenomenon is partly modulated by nitric oxide which exerts a dual effect: facilitation or inhibition of the nicotinic activation. In all the neurons tested, C(2) ceramide decreased the number of action potentials fired during a train of pulses, demonstrating an indirect inhibitory effect on the nicotinic activation. The use of 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (nitric oxide scavenger) suppressed the inhibitory effect of C(2) ceramide, demonstrating that this effect is mediated through the nitric oxide pathway. C(2) dihydro-ceramide, an inactive analog of ceramide, was without effect on the nicotinic activation of the ganglionic neurons. These results demonstrate that ceramide exerts a complex modulation of the nicotinic activation of the prevertebral neurons: direct facilitation and indirect inhibition involving the nitric oxide pathway. In fact, C(2) ceramide plays a key gating role in the dual effect of the nitric oxide pathway by activating the inhibitory effect. The existence of this gating mechanism involving ceramide and nitric oxide opens new perspectives in terms of our understanding of the modulation of synaptic transmission within the prevertebral ganglia. Our study demonstrates that sphingolipids are involved in complex modulations of the synaptic activation within the prevertebral ganglia, and thus contribute to their integrative properties.
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Affiliation(s)
- C Fasano
- Laboratoire de Physiologie Neurovégétative, UMR CNRS 6153-INRA 1147, Université Aix-Marseille III, Faculté des Sciences et Techniques St. Jérôme, Marseille, France
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12
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Li L, Shou Y, Borowitz JL, Isom GE. Reactive oxygen species mediate pyridostigmine-induced neuronal apoptosis: involvement of muscarinic and NMDA receptors. Toxicol Appl Pharmacol 2001; 177:17-25. [PMID: 11708896 DOI: 10.1006/taap.2001.9283] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Pyridostigmine bromide (PB) is a reversible cholinesterase inhibitor used for treatment of myasthenia gravis and for prophylactic protection against organophosphate nerve agent. We previously showed PB can induce apoptotic death in rat brain following systemic treatment. To study mechanisms by which PB induces brain cell death, cultured rat cerebellar granule cells were used. Cytotoxicity was determined after exposure to PB (10-1000 microM) for 24 h; a high concentration of PB (>500 microM) significantly increased lactate dehydrogenase release, which was reduced by pretreatment with the antioxidant, N-t-butyl-alpha-phenyl-nitrone (PBN). Apoptosis, as determined by TUNEL staining, was concentration dependent (10-250 microM) after a 24-h exposure and cytotoxicity was confirmed by gel electrophoresis of DNA, release of cytochrome c from mitochondria, elevation of caspase activity, and electron microscopy. The oxidant-sensitive fluorescent dye 2',7'-dichlorofluorescin diacetate was used to detect reactive oxidative species (ROS) generation. Pretreatment with PBN, superoxide dismutase, catalase, or the nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) blocked PB-induced ROS generation and apoptotic cell death. Pretreatment with atropine or MK-801 blocked ROS generation and the subsequent neurotoxicity, showing that both muscarinic and NMDA receptors mediate the response. DNA extracted from PB-treated cells revealed oligonucleosomal fragmentation on gel electrophoresis and antioxidants attenuated the DNA fragmentation, providing further evidence for a link of ROS generation and apoptosis. These results indicate that muscarinic receptor-mediated ROS generation is an initiating factor in PB-induced apoptotic cell death and activation of the NMDA glutamate receptor is directly linked to the response.
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Affiliation(s)
- L Li
- Neurotoxicology Laboratory, Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907-1333, USA
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13
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Holmberg K, Steinbusch HM, de Vente J, Hökfelt T. Distribution of cGMP in guinea pig autonomic ganglia after stimulation with sodium nitroprusside. Auton Neurosci 2001; 89:7-15. [PMID: 11474649 DOI: 10.1016/s1566-0702(01)00242-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Nitric oxide (NO) is an intercellular messenger molecule in the nervous system and exerts its action in many regions by generating cyclic GMP (cGMP) via soluble guanylyl cyclase. In this study, on the male guinea pig, we have analyzed the localization of cGMP in some autonomic ganglia with immunohistochemistry after stimulation with sodium nitroprusside (SNP) as NO donor, and made correlations with the NO synthesizing enzyme NO synthase (NOS), tyrosine hydroxylase (TH) and some neuropeptides. The putative target neurons for NO were examined in the anterior pelvic ganglia (APGs), as well as some pre- and paravertebral sympathetic ganglia. The results show that cGMP-like immunoreactivity (LI) in the APG was in most cases observed in the TH-positive, NOS-negative neuron population after SNP stimulation, whereas the NOS-expressing cholinergic population mostly lacked detectable cGMP-LI. In the pre- and paravertebral ganglia, SNP stimulation increased cGMP levels to a much lesser extent than in the APGs. cGMP was also observed in blood vessels, in the ganglion capsule, and in some cases. possibly in satellite cells. We propose, as one alternative, that there is a functional, intraganglionic regulatory loop between the parasympathetic and sympathetic divisions of the APG, using the NO/cGMP pathway.
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Affiliation(s)
- K Holmberg
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
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