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Szczepanska-Sadowska E, Cudnoch-Jedrzejewska A, Sadowski B. Differential role of specific cardiovascular neuropeptides in pain regulation: Relevance to cardiovascular diseases. Neuropeptides 2020; 81:102046. [PMID: 32284215 DOI: 10.1016/j.npep.2020.102046] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Revised: 03/27/2020] [Accepted: 03/29/2020] [Indexed: 12/11/2022]
Abstract
In many instances, the perception of pain is disproportionate to the strength of the algesic stimulus. Excessive or inadequate pain sensation is frequently observed in cardiovascular diseases, especially in coronary ischemia. The mechanisms responsible for individual differences in the perception of cardiovascular pain are not well recognized. Cardiovascular disorders may provoke pain in multiple ways engaging molecules released locally in the heart due to tissue ischemia, inflammation or cellular stress, and through neurogenic and endocrine mechanisms brought into action by hemodynamic disturbances. Cardiovascular neuropeptides, namely angiotensin II (Ang II), angiotensin-(1-7) [Ang-(1-7)], vasopressin, oxytocin, and orexins belong to this group. Although participation of these peptides in the regulation of circulation and pain has been firmly established, their mutual interaction in the regulation of pain in cardiovascular diseases has not been profoundly analyzed. In the present review we discuss the regulation of the release, and mechanisms of the central and systemic actions of these peptides on the cardiovascular system in the context of their central and peripheral nociceptive (Ang II) and antinociceptive [Ang-(1-7), vasopressin, oxytocin, orexins] properties. We also consider the possibility that they may play a significant role in the modulation of pain in cardiovascular diseases. The rationale for focusing attention on these very compounds was based on the following premises (1) cardiovascular disturbances influence the release of these peptides (2) they regulate vascular tone and cardiac function and can influence the intensity of ischemia - the factor initiating pain signals in the cardiovascular system, (3) they differentially modulate nociception through peripheral and central mechanisms, and their effect strongly depends on specific receptors and site of action. Accordingly, an altered release of these peptides and/or pharmacological blockade of their receptors may have a significant but different impact on individual sensation of pain and comfort of an individual patient.
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Affiliation(s)
- Ewa Szczepanska-Sadowska
- Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Banacha 1b, Warsaw, Poland.
| | - Agnieszka Cudnoch-Jedrzejewska
- Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Banacha 1b, Warsaw, Poland
| | - Bogdan Sadowski
- School of Engineering and Health, Bitwy Warszawskiej 1920 r. 18, Warsaw, Poland
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Ishii K, Asahara R, Komine H, Liang N, Matsukawa K. Pivotal role of the ventral tegmental area in spontaneous motor activity and concomitant cardiovascular responses in decerebrate rats. Brain Res 2020; 1729:146616. [DOI: 10.1016/j.brainres.2019.146616] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 12/11/2019] [Accepted: 12/16/2019] [Indexed: 10/25/2022]
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GABA A receptor in the Pedunculopontine tegmental (PPT) nucleus: Effects on cardiovascular system. Pharmacol Rep 2018; 70:1001-1009. [PMID: 32002952 DOI: 10.1016/j.pharep.2018.03.010] [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: 10/16/2017] [Revised: 03/09/2018] [Accepted: 03/28/2018] [Indexed: 11/19/2022]
Abstract
BACKGROUND The pedunculopontine tegmental (PPT) nucleus is a heterogeneous nucleus with several functions including cardiovascular regulation. The presence of GABAA receptor has been shown in the PPT. Therefore, the cardiovascular effects of this receptor were examined. METHODS Rats were divided into: Control; Muscimol; Bicuculline (BMI); Hexamethonium (Hexa) + BMI and Atropine + BMI groups. The femoral vein and artery were cannulated for drug administration and recording of cardiovascular parameters, respectively. Muscimol (a GABAA agonist; 1.5 and 2.5 nmol), BMI (a GABAA antagonist; 0.1 and 0.2 nmol) were stereotaxically microinjected into the PPT. To evaluate the peripheral cardiovascular mechanisms of GABAA receptors, Hexa (a ganglionic blocker; 10 mg/kg) and atropine (a muscarinic receptor antagonist; 1 mg/kg) were intravenously (iv) injected before BMI (0.2 nmol). The average changes of mean arterial pressure (ΔMAP), systolic blood pressure (ΔSBP) and heart rate (ΔHR) in different intervals were calculated and compared both within and between case group and control group (repeated measures ANOVA). The peak changes in each group were also calculated and compared with those of the control group (independent sample t-test). RESULTS Both doses of BMI significantly increased ΔMAP, ΔSBP and ΔHR compared to control, while the only higher dose of muscimol significantly decreased ΔSBP. Iv injection of Hexa significantly attenuated ΔMAP, ΔSBP and ΔHR responses induced by BMI but atropine did not affect. CONCLUSIONS Our results demonstrate that GABAA receptor of the PPT has a tonic inhibitory effect on the cardiovascular system and its peripheral effect mostly is mediated by sympathetic system.
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Henderson LA, Fatouleh RH, Lundblad LC, McKenzie DK, Macefield VG. Effects of 12 Months Continuous Positive Airway Pressure on Sympathetic Activity Related Brainstem Function and Structure in Obstructive Sleep Apnea. Front Neurosci 2016; 10:90. [PMID: 27013952 PMCID: PMC4785184 DOI: 10.3389/fnins.2016.00090] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 02/22/2016] [Indexed: 12/21/2022] Open
Abstract
Muscle sympathetic nerve activity (MSNA) is greatly elevated in patients with obstructive sleep apnea (OSA) during normoxic daytime wakefulness. Increased MSNA is a precursor to hypertension and elevated cardiovascular morbidity and mortality. However, the mechanisms underlying the high MSNA in OSA are not well understood. In this study we used concurrent microneurography and magnetic resonance imaging to explore MSNA-related brainstem activity changes and anatomical changes in 15 control and 15 OSA subjects before and after 6 and 12 months of continuous positive airway pressure (CPAP) treatment. We found that following 6 and 12 months of CPAP treatment, resting MSNA levels were significantly reduced in individuals with OSA. Furthermore, this MSNA reduction was associated with restoration of MSNA-related brainstem activity and structural changes in the medullary raphe, rostral ventrolateral medulla, dorsolateral pons, and ventral midbrain. This restoration occurred after 6 months of CPAP treatment and was maintained following 12 months CPAP. These findings show that continual CPAP treatment is an effective long-term treatment for elevated MSNA likely due to its effects on restoring brainstem structure and function.
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Affiliation(s)
- Luke A Henderson
- Neural Imaging Laboratory, Discipline of Anatomy and Histology, The University of Sydney Sydney, NSW, Australia
| | - Rania H Fatouleh
- School of Medicine, Western Sydney University Sydney, NSW, Australia
| | - Linda C Lundblad
- Neural Imaging Laboratory, Discipline of Anatomy and Histology, The University of SydneySydney, NSW, Australia; School of Medicine, Western Sydney UniversitySydney, NSW, Australia
| | - David K McKenzie
- Department of Respiratory Medicine, Prince of Wales Private Hospital Sydney, NSW, Australia
| | - Vaughan G Macefield
- School of Medicine, Western Sydney UniversitySydney, NSW, Australia; Neuroscience Research AustraliaSydney, NSW, Australia
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Yeganeh F, Ranjbar A, Hatam M, Nasimi A. Mechanism of the cardiovascular effects of the GABAA receptors of the ventral tegmental area of the rat brain. Neurosci Lett 2015; 600:193-8. [PMID: 26079327 DOI: 10.1016/j.neulet.2015.06.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 06/08/2015] [Accepted: 06/09/2015] [Indexed: 10/23/2022]
Abstract
The ventral tegmental area (VTA) contains GABA terminals involved in the regulation of the cardiovascular system. Previously, we demonstrated that blocking GABAA but not GABAB receptors produced a pressor response accompanied by marked bradycardia. This study was performed to find the possible mechanisms involved in these responses by blocking ganglionic nicotinic receptors, peripheral muscarinic receptors or peripheral V1 vasopressin receptors. Experiments were performed on urethane anesthetized male Wistar rats. Drugs were microinjected unilaterally into the VTA (100 nl). The average changes in mean arterial pressure (MAP) and heart rate (HR) were compared between pre- and post-treatment using paired t-test. Injection of bicuculline methiodide (BMI), a GABAA antagonist, into the VTA caused a significant increase in MAP and a decrease in HR. Administration (i.v.) of the nicotinic receptor blocker, hexamethonium, enhanced the pressor response but abolished the bradycardic response to BMI, which ruled out involvement of the sympathetic nervous system. Blockade of the peripheral muscarinic receptors by homatropine (i.v.) abolished the bradycardic effect of BMI, but had no effect on the pressor response, indicating that bradycardia was produced by the parasympathetic outflow to the heart. Both the pressor and bradycardic responses to BMI were blocked by V1 receptor antagonist (i.v.), indicating that administration of BMI in the VTA disinhibited the release of vasopressin into the circulation. In conclusion, we demonstrated that GABAergic mechanism of the VTA exerts a tonic inhibition on vasopressin release through activation of GABAA receptors. The sympathetic system is not involved in the decrease of blood pressure by GABA of the VTA.
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Affiliation(s)
- Fahimeh Yeganeh
- Department of Physiology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Afsaneh Ranjbar
- Department of Physiology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Masoumeh Hatam
- Department of Physiology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
| | - Ali Nasimi
- Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
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Enhanced upregulation of CRH mRNA expression in the nucleus accumbens of male rats after a second injection of methamphetamine given thirty days later. PLoS One 2014; 9:e84665. [PMID: 24475032 PMCID: PMC3903495 DOI: 10.1371/journal.pone.0084665] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 11/17/2013] [Indexed: 01/18/2023] Open
Abstract
Methamphetamine (METH) is a widely abused amphetamine analog. Few studies have investigated the molecular effects of METH exposure in adult animals. Herein, we determined the consequences of an injection of METH (10 mg/kg) on transcriptional effects of a second METH (2.5 mg/kg) injection given one month later. We thus measured gene expression by microarray analyses in the nucleus accumbens (NAc) of 4 groups of rats euthanized 2 hours after the second injection: saline-pretreated followed by saline-challenged (SS) or METH-challenged (SM); and METH-pretreated followed by saline-challenged (MS) or METH-challenged (MM). Microarray analyses revealed that METH (2.5 mg/kg) produced acute changes (1.8-fold; P<0.01) in the expression of 412 (352 upregulated, 60 down-regulated) transcripts including cocaine and amphetamine regulated transcript, corticotropin-releasing hormone (Crh), oxytocin (Oxt), and vasopressin (Avp) that were upregulated. Injection of METH (10 mg/kg) altered the expression of 503 (338 upregulated, 165 down-regulated) transcripts measured one month later (MS group). These genes also included Cart and Crh. The MM group showed altered expression of 766 (565 upregulated, 201 down-regulated) transcripts including Avp, Cart, and Crh. The METH-induced increased Crh expression was enhanced in the MM group in comparison to SM and MS groups. Quantitative PCR confirmed the METH-induced changes in mRNA levels. Therefore, a single injection of METH produced long-lasting changes in gene expression in the rodent NAc. The long-term increases in Crh, Cart, and Avp mRNA expression suggest that METH exposure produced prolonged activation of the endogenous stress system. The METH-induced changes in oxytocin expression also suggest the possibility that this neuropeptide might play a significant role in the neuroplastic and affiliative effects of this drug.
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Abstract
Blood pressure displays large fluctuations during REM sleep, a period when skeletal muscle loses activity systemically. Blood pressure rises spontaneously in spike-like surges even with no body movement. The mechanism underlying this unique characteristic of cardiovascular control during REM sleep remains unclear. Where does the source for this blood pressure surge during REM sleep exist? Is it related to dreaming, which is one of the primary characteristics of REM sleep? Are peripheral mechanisms involved in this phenomenon? Here, evidence related to the above-mentioned questions is reviewed.
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Affiliation(s)
- Hiroyoshi Séi
- Department of Integrative Physiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8503, Japan.
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Godoy T, Riva A, Ekström J. Atypical antipsychotics--effects of amisulpride on salivary secretion and on clozapine-induced sialorrhea. Oral Dis 2012; 18:680-91. [PMID: 22458406 DOI: 10.1111/j.1601-0825.2012.01926.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
OBJECTIVE Amisulpride is suggested for treatment of clozapine-induced sialorrhea. However, objective measurements of its effectiveness are lacking and, preclinically, amisulpride has no effect. We currently hypothesise that amisulpride acts by reducing the nervous- rather than the clozapine-driven salivary secretion. MATERIAL AND METHODS Effects of intravenous amisulpride (as well as of clozapine and raclopride, a dopamine D2/D3 antagonist) were investigated in rats, including those subjected to chronic preganglionic parasympathetic denervation (submandibular glands) or combined postganglionic parasympathetic and sympathetic denervation (parotid glands). In duct-cannulated glands, secretion was evoked reflexly, at low and maximum flow rates, and by electrical stimulation of the parasympathetic and sympathetic innervations, and administration of autonomimetics (including substance P). RESULTS Unlike clozapine, amisulpride had no effect on the reflexly evoked secretion at maximum rate. With respect to reflex secretion at low rate and to the secretion evoked by muscarinic, α-adrenergic, β-adrenergic and substance P receptors, amisulpride (in contrast to raclopride) dose dependently potentiated the responses. Amisulpride had no effect on gland blood flow. CONCLUSIONS No support for any inhibitory influence of amisulpride was found. Conversely, amisulpride universally enhanced secretion, suggesting that amisulpride is a potential drug for dry-mouth treatment. The mechanism behind the potentiation is currently unknown.
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Affiliation(s)
- T Godoy
- Department of Pharmacology, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, Göteborg, Sweden
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Matsukawa K, Nakamoto T, Liang N. Electrical stimulation of the mesencephalic ventral tegmental area evokes skeletal muscle vasodilatation in the cat and rat. J Physiol Sci 2011; 61:293-301. [PMID: 21541811 PMCID: PMC10717621 DOI: 10.1007/s12576-011-0149-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Accepted: 04/04/2011] [Indexed: 11/26/2022]
Abstract
To test the hypothesis that the mesencephalic ventral tegmental area (VTA) plays a role in autonomic control of the cardiovascular system, we examined the cardiovascular effects of electrical stimulation of the mesencephalic ventral areas in anesthetized, paralyzed cats and rats. Electrical stimulation of the VTA for 30 s (100-μA current intensity; 40-50-Hz pulse frequency; 0.5-1-ms pulse duration) increased femoral blood flow by 130-162% in anesthetized cats and rats, whereas the identical stimulation of the substantial nigra (SN) failed to increase femoral blood flow. Electrical stimulation of the VTA also increased the arterial blood pressure and heart rate in anesthetized rats, but did not alter them in anesthetized cats. Accordingly, femoral vascular conductance was increased by 102-134% in both cats and rats. Atropine methyl nitrate (0.1 mg/kg) injected intravenously in the cats markedly attenuated the increases in femoral blood flow and vascular conductance. VTA stimulation was able to produce substantial increases in femoral blood flow and vascular conductance following a decerebration procedure performed at the premammillary and precollicular level in the cats, although their responses tended to attenuate to 55-69% of the control before the decerebration. Thus, it is likely that electrical stimulation of the VTA, but not the SN, is capable of evoking skeletal muscle vasodilatation, particularly via a sympathetically mediated cholinergic mechanism in the cat, and that the ascending projection from the VTA to the forebrain may not be responsible for the muscle vasodilatation.
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Affiliation(s)
- Kanji Matsukawa
- Department of Physiology, Graduate School of Health Sciences, Hiroshima University, Kasumi, Minami-ku, Hiroshima, Japan.
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De Brito Gariepy H, Couture R. Blockade of tachykinin NK3 receptor reverses hypertension through a dopaminergic mechanism in the ventral tegmental area of spontaneously hypertensive rats. Br J Pharmacol 2011; 161:1868-84. [PMID: 20804497 DOI: 10.1111/j.1476-5381.2010.01008.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Intracerebroventricularly injected tachykinin NK(3) receptor (R) antagonists normalize mean arterial blood pressure (MAP) in spontaneously hypertensive rats (SHR). This study was pursued to define the role played by NK(3)R located on dopamine neurones of the ventral tegmental area (VTA) in the regulation of MAP in SHR. EXPERIMENTAL APPROACH SHR (16 weeks) were implanted permanently with i.c.v. and/or VTA guide cannulae. Experiments were conducted 24 h after catheterization of the abdominal aorta to measure MAP and heart rate (HR) in freely behaving rats. Cardiovascular responses to i.c.v. or VTA-injected NK(3)R agonist (senktide) and antagonists (SB222200 and R-820) were measured before and after systemic administration of selective antagonists for D(1)R (SCH23390), D(2)R (raclopride) or non-selective D(2)R (haloperidol), and after destruction of the VTA with ibotenic acid. KEY RESULTS I.c.v. or VTA-injected SB222200 and R-820 (500 pmol) evoked anti-hypertension, which was blocked by raclopride. Senktide (10, 25, 65 and 100 pmol) elicited greater increases of MAP and HR when injected in the VTA, and the cardiovascular response was blocked by R-820, SCH23390 and haloperidol. VTA-injected SB222200 prevented the pressor response to i.c.v. senktide, and vice versa, i.c.v. senktide prevented the anti-hypertension to VTA SB222200. Destruction of the VTA prevented the pressor response to i.c.v. senktide and the anti-hypertension to i.c.v. R-820. CONCLUSIONS AND IMPLICATIONS The NK(3)R in the VTA is implicated in the maintenance of hypertension by increasing midbrain dopaminergic transmission in SHR. Hence, this receptor may represent a therapeutic target in the treatment of hypertension.
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Affiliation(s)
- Helaine De Brito Gariepy
- Département de Physiologie, Faculté de médecine, Université de Montréal, Montréal, Quebec, Canada
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Nakamoto T, Matsukawa K, Liang N, Wakasugi R, Wilson LB, Horiuchi J. Coactivation of renal sympathetic neurons and somatic motor neurons by chemical stimulation of the midbrain ventral tegmental area. J Appl Physiol (1985) 2011; 110:1342-53. [PMID: 21393462 DOI: 10.1152/japplphysiol.01233.2010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We examined whether neurons in the midbrain ventral tegmental area (VTA) play a role in generating central command responsible for autonomic control of the cardiovascular system in anesthetized rats and unanesthetized, decerebrated rats with muscle paralysis. Small volumes (60 nl) of an N-methyl-D-aspartate receptor agonist (L-homocysteic acid) and a GABAergic receptor antagonist (bicuculline) were injected into the VTA and substantia nigra (SN). In anesthetized rats, L-homocysteic acid into the VTA induced short-lasting increases in renal sympathetic nerve activity (RSNA; 66 ± 21%), mean arterial pressure (MAP; 5 ± 2 mmHg), and heart rate (HR; 7 ± 2 beats/min), whereas bicuculline into the VTA produced long-lasting increases in RSNA (130 ± 45%), MAP (26 ± 2 mmHg), and HR (66 ± 6 beats/min). Bicuculline into the VTA increased blood flow and vascular conductance of the hindlimb triceps surae muscle, suggesting skeletal muscle vasodilatation. However, neither drug injected into the SN affected all variables. Renal sympathetic nerve and cardiovascular responses to chemical stimulation of the VTA were not essentially affected by decerebration at the premammillary-precollicular level, indicating that the ascending projection to the forebrain from the VTA was not responsible for evoking the sympathetic and cardiovascular responses. Furthermore, bicuculline into the VTA in decerebrate rats produced long-lasting rhythmic bursts of RSNA and tibial motor nerve discharge, which occurred in good synchrony. It is likely that the activation of neurons in the VTA is capable of eliciting synchronized stimulation of the renal sympathetic and tibial motor nerves without any muscular feedback signal.
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Affiliation(s)
- Tomoko Nakamoto
- Department of Physiology, Graduate School of Health Sciences, Hiroshima University, Hiroshima, Japan
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Vaarmann A, Gandhi S, Gourine AV, Abramov AY. Novel pathway for an old neurotransmitter: Dopamine-induced neuronal calcium signalling via receptor-independent mechanisms. Cell Calcium 2010; 48:176-82. [DOI: 10.1016/j.ceca.2010.08.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Revised: 07/19/2010] [Accepted: 08/17/2010] [Indexed: 10/19/2022]
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Ikemoto S. Dopamine reward circuitry: two projection systems from the ventral midbrain to the nucleus accumbens-olfactory tubercle complex. BRAIN RESEARCH REVIEWS 2007; 56:27-78. [PMID: 17574681 PMCID: PMC2134972 DOI: 10.1016/j.brainresrev.2007.05.004] [Citation(s) in RCA: 1047] [Impact Index Per Article: 61.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2006] [Revised: 05/03/2007] [Accepted: 05/04/2007] [Indexed: 01/17/2023]
Abstract
Anatomical and functional refinements of the meso-limbic dopamine system of the rat are discussed. Present experiments suggest that dopaminergic neurons localized in the posteromedial ventral tegmental area (VTA) and central linear nucleus raphe selectively project to the ventromedial striatum (medial olfactory tubercle and medial nucleus accumbens shell), whereas the anteromedial VTA has few if any projections to the ventral striatum, and the lateral VTA largely projects to the ventrolateral striatum (accumbens core, lateral shell and lateral tubercle). These findings complement the recent behavioral findings that cocaine and amphetamine are more rewarding when administered into the ventromedial striatum than into the ventrolateral striatum. Drugs such as nicotine and opiates are more rewarding when administered into the posterior VTA or the central linear nucleus than into the anterior VTA. A review of the literature suggests that (1) the midbrain has corresponding zones for the accumbens core and medial shell; (2) the striatal portion of the olfactory tubercle is a ventral extension of the nucleus accumbens shell; and (3) a model of two dopamine projection systems from the ventral midbrain to the ventral striatum is useful for understanding reward function. The medial projection system is important in the regulation of arousal characterized by affect and drive and plays a different role in goal-directed learning than the lateral projection system, as described in the variation-selection hypothesis of striatal functional organization.
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Affiliation(s)
- Satoshi Ikemoto
- Behavioral Neuroscience Research Branch, National Institute on Drug Abuse, National Institutes of Health, US Department of Health and Human Services, Baltimore, Maryland 21224, USA.
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Deschamps K, Couture R. The ventral tegmental area as a putative target for tachykinins in cardiovascular regulation. Br J Pharmacol 2005; 145:712-27. [PMID: 15895109 PMCID: PMC1576198 DOI: 10.1038/sj.bjp.0706249] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Tachykinin receptor agonists and antagonists were microinjected into the ventral tegmental area (VTA) to study the relative participation of the three tachykinin receptors in cardiovascular regulation in freely behaving rat. Selective agonists (1-100 pmol) for NK1 ([Sar9, Met (O2)11]SP), NK2 ([beta-Ala8]NKA (4-10)) and NK3 (senktide) receptors evoked increases in blood pressure, heart rate (HR) along with behavioural manifestations (face washing, sniffing, head scratching, rearing, wet dog shake). At 1 pmol, NK1 and NK3 agonists did not affect behaviour and blood pressure but only HR. Tachykinin agonists-induced cardiovascular responses were selectively and reversibly blocked by the prior injection of antagonists for NK1 receptors (LY 303870 ((R)-1-[N-(2-methoxybenzyl)acetylamino]-3-(1H-indol-3-yl)-2-[N-(2-(4-(piperidin-1-yl)piperidin-1-yl)acetyl)amino]propane), 5 nmol), NK2 receptors (SR 48968 ([(S)-N-methyl-N-[4-acetylamino-4-phenylpiperidino-2-(3,4-dichlorophenyl)butyl]benzamide]), 250 pmol) and NK3 receptors (SB 235375 ((-)-(S)-N-(alpha-ethylbenzyl)-3-(carboxymethoxy)-2-phenylquinoline-4-carboxamide), 25 nmol). With the exception of the NK2 agonist, most behavioural effects were also blocked by antagonists. Tachykinin agonists-induced cardiovascular responses were inhibited by intravenous (i.v.) treatments with antagonists for D1 dopamine receptor (SCH23390, 0.2 mg kg(-1)) and beta1-adrenoceptor (atenolol, 5 mg kg(-1)) but not for D2 dopamine receptor (raclopride, 0.16 mg kg(-1)). Behavioural responses were blocked by SCH23390 only. The present study provides the first pharmacological evidence that the three tachykinin receptors in the rat VTA can affect the autonomic control of blood pressure and HR by increasing midbrain dopaminergic transmission. This mechanism may be involved in the coordination of behavioural and cardiovascular responses to stress and noxious stimulation.
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Affiliation(s)
- Kathleen Deschamps
- Department of Physiology, Faculty of Medicine, Université de Montréal, CP 6128, Succursale Centre-ville, Montréal, Québec, Canada H3C 3J7
| | - Réjean Couture
- Department of Physiology, Faculty of Medicine, Université de Montréal, CP 6128, Succursale Centre-ville, Montréal, Québec, Canada H3C 3J7
- Author for correspondence:
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Chang CK, Wang NL, Lin MT. Inhibition of the dopamine system in rat amygdala attenuates the picrotoxin-induced locomoter hyperactivity and hypertension. Clin Exp Pharmacol Physiol 2005; 31:284-8. [PMID: 15191399 DOI: 10.1111/j.1440-1681.2004.03994.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The aim of the present study was to investigate whether picrotoxin-induced locomotor hyperactivity and hypertension can be inhibited by dopaminergic inhibition in rat amygdala. Locomotor activity was detected using a modularized infrared light matrix system in freely moving rats. In anaesthetized rats, blood pressure was measured while dopamine release was detected using in vivo voltammetry with carbon fibre electrodes. Systemic administration of picrotoxin (1-4 mg/kg) increased both locomotor activity (including horizontal motion, vertical motion and total distance travelled) and the number of turnings (both clockwise and anticlockwise), but inhibited postural freezing. The locomotor hyperactivity induced by systemic administration of picrotoxin was mimicked by direct injection of a small dose (1-3 micro g in 1.0 micro L) of picrotoxin into the amygdala. In vivo voltammetry data revealed that systemic administration of picrotoxin increased the release of dopamine in the amygdala of rat brain accompanied by hypertension. Local injection of kainic acid into the paramedian reticular nucleus (PRN) of the medulla oblongata decreased both the spontaneous release of dopamine in the amygdala and spontaneous levels of locomotor activity in rats. Furthermore, the picrotoxin-induced locomotor hyperactivity, hypertension and increased amygdaloid dopamine release were all suppressed following chemical stimulation of the PRN with kainic acid. Blockade of dopamine receptors with systemic or intra-amygdaloid injection of haloperidol (a dopamine receptor antagonist) significantly attenuated the picrotoxin-induced locomotor hyperactivity and hypertension. These results demonstrate that picrotoxin-induced hyperactivity and hypertension involve an increase in amygdaloid dopamine transmission that can be modulated by ascending projections from the PRN in the medulla oblongata.
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Affiliation(s)
- C K Chang
- Department of Surgery, MacKay Memorial Hospital, Taipei, Taiwan
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Abstract
The effect of acute treatment with clozapine, risperidone and haloperidol on cardiovascular response to open field novelty stress was investigated in rats using radio-telemetry and video-tracking analysis. Pretreatment with clozapine dose-dependently inhibited the pressor response, tachycardia and increase in dP/dt and caused a marked reduction of exploratory locomotor activity. Similar effects were observed after risperidone treatment. Haloperidol treatment markedly reduced locomotor activity but its cardiovascular effects were limited to a more rapid return of heart rate towards baseline levels. These data suggest that particularly the atypical antipsychotic drugs, clozapine and risperidone, but not the typical antipsychotic, haloperidol, reduce cardiovascular stress responses, an effect that could reflect their anxiolytic action. Such anxiolytic effects could contribute to the beneficial clinical effects of atypical antipsychotic drugs in patients with schizophrenia.
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Affiliation(s)
- Maarten van den Buuse
- Behavioural Neuroscience Laboratory, Mental Health Research Institute of Victoria, Parkville, Victoria 3052, Australia.
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Abstract
Dopamine is an important transmitter in the CNS and PNS, critically regulating numerous neuropsychiatric and physiological functions. These actions of dopamine are mediated by five distinct receptor subtypes. Of these receptors, probably the least understood in terms of physiological functions is the D5 receptor subtype. To better understand the role of the D5 dopamine receptor (DAR) in normal physiology and behavior, we have now used gene-targeting technology to create mice that lack this receptor subtype. We find that the D5 receptor-deficient mice are viable and fertile and appear to develop normally. No compensatory alterations in other dopamine receptor subtypes were observed. We find, however, that the mutant mice develop hypertension and exhibit significantly elevated blood pressure (BP) by 3 months of age. This hypertension appears to be caused by increased sympathetic tone, primarily attributable to a CNS defect. Our data further suggest that this defect involves an oxytocin-dependent sensitization of V1 vasopressin and non-NMDA glutamatergic receptor-mediated pathways, potentially within the medulla, leading to increased sympathetic outflow. These results indicate that D5 dopamine receptors modulate neuronal pathways regulating blood pressure responses and may provide new insights into mechanisms for some forms of essential hypertension in humans, a disease that afflicts up to 25% of the aged adult population in industrialized societies.
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Kawahara Y, Kawahara H, Westerink BHC. Hypotension-induced dopamine release in prefrontal cortex is mediated by local glutamatergic projections at the level of nerve terminals. J Neurochem 2002; 81:285-91. [PMID: 12064475 DOI: 10.1046/j.1471-4159.2002.00828.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In a previous study it was shown that nitroprusside-induced hypotension strongly enhances the release of dopamine (DA) in the prefrontal cortex (PFC). In the present study we have further investigated the mechanism involved in this effect. Glutamate receptor antagonists were infused into the ventral tegmental area (VTA) or PFC, while DA release was measured in the ipsilateral PFC and hypotension was applied by intravenous infusion of nitroprusside. Infusion into the VTA of neither a NMDA receptor antagonist (CPP), nor a non-NMDA antagonist (DNQX) affected the hypotension-induced increase of DA in the PFC. Intracortical infusion of CPP also failed to affect significantly, whereas local infusion of DNQX inhibited the hypotension-enhanced release of DA dose-dependently. The stimulation of DA release was relatively small in the VTA as well as in the nucleus accumbens when compared with the response in the PFC. It is concluded that DA released from mesocortical neurons can be modulated by two different mechanisms: first, by glutamate afferents to the VTA that modify the nerve-impulse flow of DA neurons; and, second, by glutamate afferents to the PFC that act at the level of the DA nerve terminals. The behaviour context (arousal or stress versus hypotension) determines which type of interaction predominates.
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Affiliation(s)
- Yukie Kawahara
- Department of Biomonitoring and Sensoring, University Center for Pharmacy, University of Groningen, Antonius, The Netherlands.
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Thomas GN, Tomlinson B, Critchley JA. Modulation of blood pressure and obesity with the dopamine D2 receptor gene TaqI polymorphism. Hypertension 2000; 36:177-82. [PMID: 10948074 DOI: 10.1161/01.hyp.36.2.177] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Pharmacological data suggest that obesity and blood pressure (BP) may be modulated through the dopamine D2 receptor (DD2R), which may represent an underlying mechanism that links these conditions. A TAQ:I polymorphism near the DD2R gene has been associated with indices of obesity in white populations. We compared anthropometric and fasting plasma biochemical parameters between 209 nondiabetic hypertensive and 174 gender-matched normotensive Chinese subjects. The hypertensives had increased dyslipidemia, increased fasting plasma glucose concentrations, and a greater degree of obesity. The A1 and A2 alleles of the DD2R gene TAQ:I polymorphism were identified with a polymerase chain reaction-based restriction fragment length polymorphism protocol. The A1 allele frequency was decreased in the hypertensives (42.0%) compared with the control subjects (52.0%, P=0.006), and genotype frequencies were different (P=0.05) between the 2 groups. In the combined population (n=383), systolic, diastolic, and mean arterial BPs were 6, 5, and 6 mm Hg lower, respectively, in subjects with the A1A1 genotype relative to the A2A2 genotype (all P<0.05), whereas skinfold thickness was increased at the iliac (P<0.001) and triceps (P<0.03) sites but not at the biceps or subscapular sites. Furthermore, this DD2R gene polymorphism was shown to be a significant independent predictor of diastolic BP and iliac and triceps skinfold thicknesses (all P<0.03). These contrasting associations of the DD2R TAQ:I polymorphism A1 allele with lower BP but increased markers of "gynoidal" or peripheral subcutaneous obesity (iliac and triceps skinfold thicknesses) in our Chinese population may provide some insight into the underlying relationship between BP and body fat distribution, but the exact nature of this link remains to be determined.
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Affiliation(s)
- G N Thomas
- Division of Clinical Pharmacology, Department of Medicine and Therapeutics, The Chinese University of Hong Kong, The Prince of Wales Hospital, Shatin, Hong Kong SAR.
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20
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Kirouac GJ, Pittman QJ. A projection from the ventral tegmental area to the periaqueductal gray involved in cardiovascular regulation. Am J Physiol Regul Integr Comp Physiol 2000; 278:R1643-50. [PMID: 10848534 DOI: 10.1152/ajpregu.2000.278.6.r1643] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Experiments were done in alpha-chloralose-anesthetized rats to determine a pathway mediating the cardiovascular depressor responses elicited from stimulation of the ventral tegmental area (VTA). The magnitude of the depressor responses elicited by glutamate stimulation (0.1 M/30 nl) of the VTA was examined after neuronal block produced by microinjections of lidocaine into ascending fiber bundles leaving the VTA to innervate the forebrain and thalamus. Bilateral microinjections of 1 microl of 4% lidocaine in the medial forebrain bundle (n = 6) and in the periventricular fibers of the midbrain (n = 5) did not attenuate the depressor response from stimulation of the VTA. Experiments were done using the anterograde tracer biotinylated dextran amine to identify descending projections from the VTA to cardiovascular centers in the brain stem. Examination of the nucleus of the solitary tract, ventrolateral medulla, and A5 catecholaminergic cell group revealed few or no fibers or terminals. Occasional fibers and some terminals were observed in the nucleus of raphe magnus, parabrachial nucleus, and locus ceruleus. A very dense bilateral projection was found to the ventrolateral periaqueductal gray (PAGvl) and dorsal raphe nucleus adjacent to the PAGvl. Bilateral injections of 4% lidocaine (n = 4) or 10 mM cobalt chloride (n = 5) into the PAGvl region attenuated the depressor responses elicited by stimulation of the VTA by approximately 50%. These experiments indicate that the depressor responses elicited from activation of the VTA are mediated in part by a pathway to a cardiovascular depressor area located in the PAGvl.
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Affiliation(s)
- G J Kirouac
- Division of Basic Medical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, A1B 3V6, Canada.
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Sanada H, Asico LD, Shigetomi S, Tanaka K, Niimura S, Watanabe H, Goldstein DS, Felder RA. The effect of docarpamine, a dopamine pro-drug, on blood pressure and catecholamine levels in spontaneously hypertensive rats. Clin Exp Hypertens 2000; 22:419-29. [PMID: 10830753 DOI: 10.1081/ceh-100100081] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
We studied the effects of bolus intravenous injection of the dopamine prodrug, docarpamine (200 microg/kg), on mean arterial pressure (MAP) and heart rate (HR) in Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHRs). In WKY rats (n=18), MAP and HR increased 5 min after docarpamine and then returned to baseline levels within 15 min. In contrast, in SHRs (n=15), MAP and HR gradually decreased, reaching a nadir 20 min after injection. Five min after docarpamine, plasma dopamine and 3,4-dihydroxy phenyl acetic (DOPAC) levels increased in both WKY rats (n=5) and SHRs (n=5). The docarpamine-induced changes in MAP and HR in both rat strains (n=5/strain) were blocked by the D1-like antagonist, SCH23390. alpha-Adrenergic (n=4) and vasopressin V1 (n=3) receptor blockade also abrogated the effects of docarpamine in WKY rats. We conclude that docarpamine differentially affects MAP and HR in WKY and SHRs. In SHRs, the depressor and bradycardiac effects of docarpamine are mediated by D1-like receptors. In WKY rats, the pressor and tachycardiac responses are caused by an interaction among D1-like, alpha-adrenergic, and V1 receptors.
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Affiliation(s)
- H Sanada
- Department of Pathology, The University of Virginia Health Sciences Center, Charlottesville, USA
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22
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van Den Buuse M, Catanzariti R. Stimulation of the ventral tegmental area enhances the effect of vasopressin on blood pressure in conscious rats. Br J Pharmacol 2000; 129:29-36. [PMID: 10694199 PMCID: PMC1621113 DOI: 10.1038/sj.bjp.0702982] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The mesolimbic dopamine system projects to a large number of forebrain areas and plays an important role in the regulation of locomotor activity, cognition and reward. We previously found evidence for a functional interaction between the mesolimbic dopamine system and circulating vasopressin and the present study was performed to test the hypothesis that mesolimbic dopamine stimulation modulates the cardiovascular effects of vasopressin. Sprague-Dawley rats were stereotaxically implanted with a guide cannula into the region of origin of the mesolimbic system, the ventral tegmental area, and instrumented with catheters into the abdominal aorta and jugular vein. One week later, separate groups of conscious rats were injected intravenously with 1, 3 or 10 ng kg(-1) of arginine-vasopressin or other vasopressor drugs before and after intra-ventral tegmental area injection of 10 nmol of neurotensin. Intra-ventral tegmental area injections of neurotensin had no significant effect on mean arterial pressure and heart rate but significantly potentiated the pressor response to intravenous administration of vasopressin when compared to saline-injections. However, the vasopressin-induced bradycardia was unaffected. Intravenous pretreatment with raclopride blocked the ability of neurotensin, injected into the ventral tegmental area, to potentiate the vasopressin-induced pressor response. Intra ventral tegmental area injections of neurotensin had no effect on the pressor response and bradycardia induced by intravenous angiotensin II or methoxamine. In conclusion, these results suggest that the mesolimbic dopamine system, in addition to its well-known role in the regulation of behaviour, modulates cardiovascular control by potentiating the effects of vasopressin on mean arterial pressure. British Journal of Pharmacology (2000) 129, 29 - 36
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Affiliation(s)
- M van Den Buuse
- Neuropharmacology Laboratory, Baker Medical Research Institute, Melbourne, Australia.
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23
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Vaughan CE, van den Buuse M, Roland BL. Brain dopamine D2 receptor mRNA levels are elevated in young spontaneously hypertensive rats. Neurosci Res 1999; 34:199-205. [PMID: 10576542 DOI: 10.1016/s0168-0102(99)00037-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Levels of brain dopamine D2 receptor expression were compared between spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) controls by quantitative in situ hybridisation, using a complementary RNA probe for D2 receptor mRNA. In SHR which were 6 weeks of age, significantly higher levels of D2 receptor mRNA were found in the caudate-putamen (42%), nucleus accumbens (23%), olfactory tubercle (17%) and substantia nigra (38%) compared to age-matched WKY controls. D2 receptor mRNA levels were also higher in the substantia nigra (27%) of 12-14-week old SHR compared to WKY. The increased levels of dopamine D2 receptor gene expression displayed in young prehypertensive SHR could implicate altered central dopaminergic activity in the pathogenesis of hypertension.
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Affiliation(s)
- C E Vaughan
- Neuropharmacology Laboratory, Baker Medical Research Institute, Prahran, Victoria, Australia
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24
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Chen X, Kombian SB, Zidichouski JA, Pittman QJ. Dopamine depresses glutamatergic synaptic transmission in the rat parabrachial nucleus in vitro. Neuroscience 1999; 90:457-68. [PMID: 10215151 DOI: 10.1016/s0306-4522(98)00594-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Nystatin-perforated patch recordings were made from rat parabrachial neurons in an in vitro slice preparation to examine the effect of dopamine on parabrachial cells and on excitatory synaptic transmission in this nucleus. In current clamp mode, dopamine reduced the amplitude of the evoked excitatory postsynaptic potential without significant change in membrane potential. In cells voltage-clamped at -65 mV, dopamine dose dependently and reversibly decreased evoked, pharmacologically isolated, excitatory postsynaptic currents with an EC50 of 31 microM. The reduction in excitatory postsynaptic current was accompanied by an increase in paired pulse ratio (a protocol used to detect presynaptic site of action) with no change in the holding current or in the decay of the evoked excitatory postsynaptic currents. In addition, dopamine altered neither postsynaptic (+/-)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate-induced currents, nor steady-state current voltage curves. Miniature excitatory postsynaptic current analysis revealed that dopamine caused a rightward shift of the frequency-distribution curve with no change in the amplitude-distribution curve, which is consistent with a presynaptic mechanism. The dopamine-induced attenuation of the excitatory postsynaptic current was almost completely blocked by the D1-like receptor antagonist SCH23390 (10 microM), although the D2-like antagonist sulpiride (10 microM) also partially blocked it. Combined application of both antagonists blocked all dopamine-induced synaptic effects. The synaptic effect of dopamine was mimicked by the D1-like agonist SKF38393 (50 microM), but the D2-1ike agonist quinpirole (50 microM) also had a small effect. Combined application of both agonists did not produce potentiated responses. Dopamine's effect on the excitatory postsynaptic current was independent of serotonin, GABA and adenosine receptors, but may have some interactions with adrenergic receptors. These results suggest that dopamine directly modulates excitatory synaptic events in the parabrachial nucleus predominantly via presynaptic D1-like receptors.
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Affiliation(s)
- X Chen
- Neuroscience Research Group, University of Calgary, Alberta, Canada
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25
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Poon J, van den Buuse M. Autonomic mechanisms in the acute cardiovascular effects of cocaine in conscious rats. Eur J Pharmacol 1998; 363:147-52. [PMID: 9881582 DOI: 10.1016/s0014-2999(98)00804-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We studied the differential involvement of central dopaminergic activation and autonomic nervous system regulatory mechanisms in the cardiovascular responses to cocaine in conscious rats. Sprague-Dawley rats, Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) were instrumented with catheters in the jugular vein and abdominal aorta at least 5 days before the experiment. Intravenous administration of cocaine (0.1-3.0 mg/kg) caused a dose-dependent increase in blood pressure that was biphasic, with a large and rapid increase peaking at 10 s, followed by a mild sustained pressor response. Pressor responses to cocaine were significantly greater in SHR when compared to WKY rats. However, pretreatment with dopamine D1 receptor antagonist SCH 23390 or the D2 receptor antagonist raclopride did not influence the effects of cocaine. Pretreatment with the alpha-adrenoceptor antagonist phentolamine or the ganglion blocker pentolinium blocked the peak response and reversed the more sustained response into a depressor effect. While pretreatment with propranolol alone did not alter the responses to cocaine, in rats pretreated with phentolamine and propranolol neither a pressor response nor a depressor response was observed. In conclusion, cocaine administration caused marked, but short lasting pressor responses that were mediated by sympathetic activation and alpha-adrenoceptor vasoconstriction with little involvement of central dopaminergic mechanisms. The rapid return of blood pressure towards baseline may be mediated by sympathoinhibition and beta-adrenoceptor-mediated vasodilatation, the latter of which being particularly prominent when alpha-adrenoceptor activation was prevented.
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Affiliation(s)
- J Poon
- Baker Medical Research Institute, Prahran, Victoria, Australia
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26
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van den Buuse M. Role of the mesolimbic dopamine system in cardiovascular homeostasis. Stimulation of the ventral tegmental area modulates the effect of vasopressin on blood pressure in conscious rats. Clin Exp Pharmacol Physiol 1998; 25:661-8. [PMID: 9750953 DOI: 10.1111/j.1440-1681.1998.tb02273.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
1. The possible role of the ventral tegmental area (VTA) and its dopaminergic projections in cardiovascular regulation is reviewed. 2. Our own work has shown that stimulation of the VTA by local microinjection of the substance P analogue DiMe-C7 caused an increase in blood pressure. The mechanism of the pressor response was an interaction of central dopaminergic activation, most likely at the level of the baroreflex, with the circulatory actions of vasopressin. 3. These findings are important for a possible role of the mesolimbic dopamine system in cardiovascular homeostasis. Several studies reviewed here show that neuronal activity of the VTA and its mesolimbic projections is altered by changes in blood pressure, salt and electrolyte balance, stress and food and water intake. 4. The VTA and mesolimbic dopamine system, while playing a widely accepted role in locomotor activity, cognition and reward mechanisms, may also be involved in the integration of sensory and behavioural information with cardiovascular homeostasis.
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Affiliation(s)
- M van den Buuse
- Baker Medical Research Institute, Prahran, Victoria, Australia.
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27
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van den Buuse M, Wilks DP, Cornish JL. Inhibition of cardiac baroreflex sensitivity after central dopaminergic stimulation. Clin Exp Pharmacol Physiol 1998; 25:624-6. [PMID: 9673440 DOI: 10.1111/j.1440-1681.1998.tb02264.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
1. Stimulation of the mesolimbic dopamine system, by micro-injection of the substance P analogue [pGlu5,MePhe8,Sar9] substance P (DiMe-C7) into the ventral tegmental area induced a prolonged increase in blood pressure and circulating levels of vasopressin. 2. In the present study, this treatment produced a significant decrease of cardiac baroreflex sensitivity in conscious rats. After pretreatment with the dopamine receptor antagonist raclopride, central stimulation failed to produce any changes in baroreflex parameters. 3. The central dopamine-mediated decrease in baroreflex sensitivity may be involved in functionally potentiating the circulatory actions of vasopressin.
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Affiliation(s)
- M van den Buuse
- Baker Medical Research Institute, Prahran, Victoria, Australia.
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28
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Bell IR, Schwartz GE, Hardin EE, Baldwin CM, Kline JP. Differential resting quantitative electroencephalographic alpha patterns in women with environmental chemical intolerance, depressives, and normals. Biol Psychiatry 1998; 43:376-88. [PMID: 9513754 DOI: 10.1016/s0006-3223(97)00245-x] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Previous research suggests that a subset of individuals with intolerance to low levels of environmental chemicals have increased levels of premorbid and/or comorbid psychiatric disorders such as depression, anxiety, and somatization. The purpose of this study was to evaluate the psychological profiles and quantitative electroencephalographic (qEEG) profiles at baseline of women with and without chemical intolerance (CI). METHODS Participants were middle-aged women who reported illness from the odor of common chemicals (CI, n = 14), depressives without such intolerances (D, n = 10), and normal controls (N, n = 11). They completed a set of psychological scales and underwent two separate qEEG recording laboratory sessions spaced 1 week apart, at the same time of day for each subject. RESULTS CI were similar to D with increased lifetime histories of physician-diagnosed depression (71% vs. 100%), Symptom Checklist 90 (revised) (SCL-90-R) somatization scores, Barsky Somatic Symptom Amplification, and perceived life stressfulness, although D had more distress than either CI or N on several other SCL-90-R subscales. CI scored significantly higher on the McLean Limbic Symptom Checklist somatic symptom subscale than did either D or N. On qEEG, CI exhibited significantly greater overall resting absolute alpha activity with eyes closed, especially at the parietal midline site (Pz), and increased (sensitized) frontal alpha from session 1 to 2, in contrast with the D and N groups. D showed right frontal asymmetry in both sessions, in comparison with CI. CONCLUSIONS The data indicate that CI with affective distress diverge from both D without chemical intolerance and N in qEEG alpha patterns at resting baseline. Although CI descriptively resemble D with increased psychological distress, the CI's greater alpha suggests the possibility of a) central nervous system hypo-, not hyper-, activation; and/or b) an overlap with EEG alpha patterns of persons with positive family histories of alcoholism.
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Affiliation(s)
- I R Bell
- Department of Psychiatry, University of Arizona Health Sciences Center, Tucson, USA
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29
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Kirouac GJ, Ciriello J. Cardiovascular depressor responses to stimulation of substantia nigra and ventral tegmental area. THE AMERICAN JOURNAL OF PHYSIOLOGY 1997; 273:H2549-57. [PMID: 9435586 DOI: 10.1152/ajpheart.1997.273.6.h2549] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Experiments were done in alpha-chloralose-anesthetized, paralyzed, and artificially ventilated rats to investigate the effect of L-glutamate (Glu) stimulation of the substantia nigra (SN) and ventral tegmental area (VTA) on arterial pressure (AP) and heart rate (HR). Glu stimulation of the SN pars compacta (SNC) elicited decreases in both mean AP (MAP; -18.9 +/- 1.3 mmHg; n = 52) and HR (-26.1 +/- 1.6 beats/min; n = 46) at 81% of the sites stimulated. On the other hand, stimulation of the SN pars lateralis or pars reticulata did not elicit cardiovascular responses. Stimulation of the adjacent VTA region elicited similar decreases in MAP (-18.0 +/- 2.6 mmHg; n = 20) and HR (-25.4 +/- 3.8 beats/min; n = 17) at approximately 74% of the sites stimulated. Intravenous administration of the dopamine D2-receptor antagonist raclopride significantly attenuated both the MAP (70%) and the HR (54%) responses elicited by stimulation of the transitional region where the SNC merges with the lateral VTA (SNC-VTA region). Intravenous administration of the muscarinic receptor blocker atropine methyl bromide had no effect on the magnitude of the MAP and HR responses to stimulation of the SNC-VTA region, whereas administration of the nicotinic receptor blocker hexamethonium bromide significantly attenuated both the depressor and the bradycardic responses. These data suggest that dopaminergic neurons in the SNC-VTA region activate a central pathway that exerts cardiovascular depressor effects that are mediated by the inhibition of sympathetic vasoconstrictor fibers to the vasculature and cardioacceleratory fibers to the heart.
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Affiliation(s)
- G J Kirouac
- Department of Physiology, University of Western Ontario, London, Canada
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30
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Cornish JL, Wilks DP, Van den Buuse M. A functional interaction between the mesolimbic dopamine system and vasopressin release in the regulation of blood pressure in conscious rats. Neuroscience 1997; 81:69-78. [PMID: 9300402 DOI: 10.1016/s0306-4522(97)00157-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The aim of the present study was to further characterize the involvement of the mesolimbic dopamine system in central blood pressure regulation, with particular emphasis on the interaction of this system with the effects of circulating vasopressin. In conscious rats we stimulated the release of endogenous dopamine from mesolimbic/mesocortical terminals by administration of the substance P analogue DiMe-C7 ([pGlu5, MePhe8, Sar9]-Substance P5-11; 10 nmol) into the ventral tegmental area. Chemical stimulation of the ventral tegmental area resulted in a significant increase in blood pressure and heart rate. These effects were prevented by either bilateral electrolytic lesions of the hypothalamic supraoptic nucleus or by systemic pretreatment with the dopamine D2 receptor antagonist raclopride (0.5 mg/kg). Stimulation of the ventral tegmental area also produced a marked increase in the expression of the proto-oncogene c-fos in the supraoptic nucleus and a significant increase in plasma vasopressin levels, suggesting activation of vasopressinergic neurons in this nucleus. However, this effect of stimulation of the ventral tegmental area was not significantly inhibited by pretreatment with raclopride. We suggest that the effects on blood pressure and heart rate of stimulation of the ventral midbrain by micro-injection of DiMe-C7 are the result of combined activation of both dopaminergic and non-dopaminergic cell bodies in this region. Stimulation of non-dopaminergic cells in the ventral midbrain may induce a moderate increase in plasma vasopressin levels by activation of the supraoptic nucleus. An additional stimulation of dopaminergic cells in the ventral midbrain allows the increase in circulating vasopressin levels to become manifest as a pressor response, possibly by inhibition of vasopressin-induced facilitation of baroreflex responses.
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Affiliation(s)
- J L Cornish
- Neuropharmacology Laboratory, Baker Medical Research Institute, Prahran, Victoria, Australia
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31
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Van den Buuse M. Pretreatment with quinpirole inhibits the central antihypertensive effects of rilmenidine and alpha-methyldopa in conscious rats. Eur J Pharmacol 1997; 322:191-9. [PMID: 9098687 DOI: 10.1016/s0014-2999(97)00009-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Treatment of conscious spontaneously hypertensive rats (SHR) with the dopamine D2 receptor agonist quinpirole causes a short-lasting pressor response and apparent desensitisation to the effects of subsequent injections of quinpirole or central antihypertensives such as clonidine. In the present study, a number of aspects of this apparent desensitisation were investigated. Thirty minutes after intravenous injection of quinpirole into spontaneously hypertensive rats, treatment with the dopamine D2 receptors antagonist raclopride caused a significant fall in blood pressure. At this time point, circulating levels of vasopressin were not significantly different compared to controls. In Brattleboro rats, the pressor response to quinpirole was reduced in the first 15 min after injection, but not difference in blood pressure was observed at later time points. In SHR which had been treated with quinpirole, the central antihypertensive effects of rilmenidine or alpha-methyldopa were significantly inhibited. By contrast, the bradycardia induced by these drugs was similar in quinpirole-treated rats and controls. Quinpirole pretreatment caused an enhancement of the hypotension but a reduction of the reflex tachycardia after intravenous treatment with hydralazine. In SHR treated with methylatropine and quinpirole, the upper plateau of the sympathetic baroreceptor-heart rate reflex curve was reduced. These results show that treatment with quinpirole has marked effects on central sympathetic vasomotor mechanisms which are the target of antihypertensive drugs such as rilmenidine and alpha-methyldopa. At least some of these effects may occur at the level of the sympathetic baroreflex. Moreover, while the effects of quinpirole on sympathetic regulation are prolonged, the initial pressor response is counteracted by an as yet unidentified compensatory mechanism which can be unmasked when quinpirole is displaced from its receptor by dopamine D2 receptor antagonist treatment.
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Affiliation(s)
- M Van den Buuse
- Baker Medical Research Institute, Prahran, Victoria, Australia.
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Cornish JL, van den Buuse M. Regional expression of c-fos in rat brain following stimulation of the ventral tegmental area. Neurosci Lett 1996; 220:17-20. [PMID: 8977138 DOI: 10.1016/s0304-3940(96)13222-5] [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: 02/03/2023]
Abstract
This study has investigated the effect of stimulating the region of origin of the mesolimbic dopaminergic system, the ventral tegmental area (VTA), with the substance P analogue DiMe-C7 on the regional expression of c-fos in the rat forebrain. We have previously shown this treatment produced a prolonged increase in blood pressure and heart rate which was mediated by both dopaminergic mechanisms and vasopressin release. Stimulation of the VTA resulted in increased levels of c-Fos immunostaining in several target regions of the mesolimbic dopaminergic system (such as the frontal cortex, olfactory tubercle, islands of Calleja and amygdala), with the notable exception of the nucleus accumbens. A marked increase in c-fos expression was also found in the supraoptic nucleus but not the paraventricular nucleus in the hypothalamus. These results support a role for a number of target areas of the mesolimbic dopaminergic system and vasopressin release in the increase in blood pressure and heart rate produced by stimulation of the VTA.
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Affiliation(s)
- J L Cornish
- Baker Medical Research Institute, Prahan, Victoria, Australia
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