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Pereira ED, Faria AM, Andrade-Franzé GMF, Menani JV, De Luca LA, Andrade CAF. Sodium palatability in male spontaneously hypertensive rats. Horm Behav 2021; 130:104952. [PMID: 33647281 DOI: 10.1016/j.yhbeh.2021.104952] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 02/05/2021] [Accepted: 02/06/2021] [Indexed: 10/22/2022]
Abstract
Spontaneously hypertensive rats (SHRs) ingest more NaCl than normotensive strains. Here we investigated NaCl intake and taste reactivity in adult male SHRs and normotensive Holtzman rats treated or not with AT1 receptor antagonist centrally in euhydrated condition and after fluid depletion. Taste reactivity was measured by the number of orofacial expressions to intra-oral infusions of 0.3 M NaCl. In euhydrated condition, intra-oral infusions of 0.3 M NaCl produced greater number of hedonic responses in SHRs than in normotensive rats, without differences in the number of aversive responses. Compared to euhydrated condition, the treatment with the diuretic furosemide + low dose of captopril (angiotensin converting enzyme blocker) increased the number of hedonic and reduced the number of aversive responses to intra-oral NaCl in normotensive rats, without changing the number of hedonic or aversive responses in SHRs. Losartan (AT1 receptor antagonist, 100 ng/1 μl) injected intracerebroventricularly in SHRs abolished 0.3 M NaCl intake induced by water deprivation + partial rehydration, whereas only transiently (first 30 min of the 60 min test) reduced hedonic responses, without changes in aversive responses to intra-oral NaCl. Losartan intracerebroventricularly also only transiently (first 30 min) reduced the number of hedonic responses to intra-oral NaCl in euhydrated SHRs. The results suggest that NaCl palatability is increased and independent from body fluid balance in SHRs. The results also suggest that central AT1 receptors are part of the mechanisms activated to increase NaCl intake and palatability in SHRs. A partial dissociation between NaCl intake and palatability in SHRs is also suggested.
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Affiliation(s)
- E D Pereira
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
| | - A M Faria
- Graduate Program in Physiology of the Brazilian Physiological Society, Unifal-MG, Alfenas, MG, Brazil
| | - G M F Andrade-Franzé
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
| | - J V Menani
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
| | - L A De Luca
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil
| | - C A F Andrade
- Department of Physiology and Pathology, School of Dentistry, São Paulo State University - UNESP, Araraquara, SP, Brazil.
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Skibitskiy VV, Gutova SR, Fendrikova AV, Skibitskiy AV. [Antihypertensive and Vasoprotective Effects of Combined Pharmacotherapy in Patients with Arterial Hypertension and Prediabetes]. ACTA ACUST UNITED AC 2020; 60:10-17. [PMID: 32394851 DOI: 10.18087/cardio.2020.4.n1112] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 04/13/2020] [Indexed: 11/18/2022]
Abstract
Aim To evaluate effects of different types of combination drug therapy on indexes of 24-h blood pressure monitoring (24-h BPM), arterial stiffness, and central aortic pressure (CAP) in patients with arterial hypertension (AH) and prediabetes.Materials and methods The study included 120 patients with AH and prediabetes. After randomization using envelopes, three treatment groups were formed: group 1, patients receiving perindopril, indapamide SR, and metformin (n=40); group 2, patients receiving perindopril, moxonidin, and metformin (n=40); and group 3, patients receiving perindopril, indapamide SR, and amlodipine (n=40). 24-h BPM, determination of arterial stiffness, and measurement of CAP were performed for all patients.Results After 24 weeks of treatment, patients of all groups showed statistically significant improvements of most indexes of 24-h BPM, arterial stiffness, and CAP. In groups 2 and 3, the treatment was associated with significantly more pronounced beneficial changes in 24-BPM, arterial stiffness, and CAP compared to group 1. Antihypertensive and vasoprotective effects of the perindopril+moxonidin+metformin and perindopril+indopamide SR+amlodipine combinations were comparable.Conclusion The observed statistically significant antihypertensive and vasoprotective effects of the perindopril+moxonidin+metformin combination along with its known positive metabolic effect allow recommendation of this combination therapy to patients with AH and prediabetes as an effective strategy for BP control.
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Affiliation(s)
- V V Skibitskiy
- State Budget Educational Institution of Higher Professional Education "Kuban State Medical University" of the Ministry of Health of the Russian Federation
| | - S R Gutova
- State budgetary health institution of the Republic of Adygea "Maykop City Clinical Hospital"
| | - A V Fendrikova
- State Budget Educational Institution of Higher Professional Education "Kuban State Medical University" of the Ministry of Health of the Russian Federation
| | - A V Skibitskiy
- State Budget Educational Institution of Higher Professional Education "Kuban State Medical University" of the Ministry of Health of the Russian Federation
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Andrade CAF, Andrade-Franzé GMF, De Paula PM, De Luca LA, Menani JV. Role of α2-adrenoceptors in the lateral parabrachial nucleus in the control of body fluid homeostasis. Braz J Med Biol Res 2014; 47:11-8. [PMID: 24519089 PMCID: PMC3932968 DOI: 10.1590/1414-431x20133308] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 10/15/2013] [Indexed: 12/03/2022] Open
Abstract
Central α2-adrenoceptors and the pontine lateral parabrachial nucleus
(LPBN) are involved in the control of sodium and water intake. Bilateral injections
of moxonidine (α2-adrenergic/imidazoline receptor agonist) or
noradrenaline into the LPBN strongly increases 0.3 M NaCl intake induced by a
combined treatment of furosemide plus captopril. Injection of moxonidine into the
LPBN also increases hypertonic NaCl and water intake and reduces oxytocin secretion,
urinary sodium, and water excreted by cell-dehydrated rats, causing a positive sodium
and water balance, which suggests that moxonidine injected into the LPBN deactivates
mechanisms that restrain body fluid volume expansion. Pretreatment with specific
α2-adrenoceptor antagonists injected into the LPBN abolishes the
behavioral and renal effects of moxonidine or noradrenaline injected into the same
area, suggesting that these effects depend on activation of LPBN
α2-adrenoceptors. In fluid-depleted rats, the palatability of sodium is
reduced by ingestion of hypertonic NaCl, limiting intake. However, in rats treated
with moxonidine injected into the LPBN, the NaCl palatability remains high, even
after ingestion of significant amounts of 0.3 M NaCl. The changes in behavioral and
renal responses produced by activation of α2-adrenoceptors in the LPBN are
probably a consequence of reduction of oxytocin secretion and blockade of inhibitory
signals that affect sodium palatability. In this review, a model is proposed to show
how activation of α2-adrenoceptors in the LPBN may affect palatability
and, consequently, ingestion of sodium as well as renal sodium excretion.
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Affiliation(s)
- C A F Andrade
- Departamento de Fisiologia e Patologia, Faculdade de Odontologia, Universidade Estadual Paulista, AraraquaraSP, Brasil, Departamento de Fisiologia e Patologia, Faculdade de Odontologia, Universidade Estadual Paulista, Araraquara, SP, Brasil
| | - G M F Andrade-Franzé
- Departamento de Fisiologia e Patologia, Faculdade de Odontologia, Universidade Estadual Paulista, AraraquaraSP, Brasil, Departamento de Fisiologia e Patologia, Faculdade de Odontologia, Universidade Estadual Paulista, Araraquara, SP, Brasil
| | - P M De Paula
- Departamento de Fisiologia e Patologia, Faculdade de Odontologia, Universidade Estadual Paulista, AraraquaraSP, Brasil, Departamento de Fisiologia e Patologia, Faculdade de Odontologia, Universidade Estadual Paulista, Araraquara, SP, Brasil
| | - L A De Luca
- Departamento de Fisiologia e Patologia, Faculdade de Odontologia, Universidade Estadual Paulista, AraraquaraSP, Brasil, Departamento de Fisiologia e Patologia, Faculdade de Odontologia, Universidade Estadual Paulista, Araraquara, SP, Brasil
| | - J V Menani
- Departamento de Fisiologia e Patologia, Faculdade de Odontologia, Universidade Estadual Paulista, AraraquaraSP, Brasil, Departamento de Fisiologia e Patologia, Faculdade de Odontologia, Universidade Estadual Paulista, Araraquara, SP, Brasil
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Andrade C, Margatho L, Andrade-Franzé G, De Luca L, Antunes-Rodrigues J, Menani J. Moxonidine into the lateral parabrachial nucleus reduces renal and hormonal responses to cell dehydration. Neuroscience 2012; 208:69-78. [DOI: 10.1016/j.neuroscience.2012.02.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Revised: 02/07/2012] [Accepted: 02/07/2012] [Indexed: 11/27/2022]
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Adrenergic mechanisms of the Kölliker-Fuse/A7 area on the control of water and sodium intake. Neuroscience 2009; 164:370-9. [DOI: 10.1016/j.neuroscience.2009.08.048] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Revised: 08/21/2009] [Accepted: 08/22/2009] [Indexed: 11/20/2022]
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de Faria DRG, Santana JS, Menani JV, de Paula PM. Antidipsogenic effects of central adenosine-5'-triphosphate. Braz J Med Biol Res 2009; 42:105-13. [PMID: 19219303 DOI: 10.1590/s0100-879x2009000100015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2008] [Accepted: 01/20/2009] [Indexed: 11/21/2022] Open
Abstract
Besides other physiological functions, adenosine-5'-triphosphate (ATP) is also a neurotransmitter that acts on purinergic receptors. In spite of the presence of purinergic receptors in forebrain areas involved with fluid-electrolyte balance, the effect of ATP on water intake has not been investigated. Therefore, we studied the effects of intracerebroventricular (icv) injections of ATP (100, 200 and 300 nmol/microL) alone or combined with DPCPX or PPADS (P1 and P2 purinergic antagonists, respectively, 25 nmol/microL) on water intake induced by water deprivation. In addition, the effect of icv ATP was also tested on water intake induced by intragastric load of 12% NaCl (2 mL/rat), acute treatment with the diuretic/natriuretic furosemide (20 mg/kg), icv angiotensin II (50 ng/microL) or icv carbachol (a cholinergic agonist, 4 nmol/microL), on sodium depletion-induced 1.8% NaCl intake, and on food intake induced by food deprivation. Male Holtzman rats (280-320 g, N = 7-11) had cannulas implanted into the lateral ventricle. Icv ATP (300 nmol/microL) reduced water intake induced by water deprivation (13.1 +/- 1.9 vs saline: 19.0 +/- 1.4 mL/2 h; P < 0.05), an effect blocked by pre-treatment with PPADS, but not DPCPX. Icv ATP also reduced water intake induced by NaCl intragastric load (5.6 +/- 0.9 vs saline: 10.3 +/- 1.4 mL/2 h; P < 0.05), acute furosemide treatment (0.5 +/- 0.2 vs saline: 2.3 +/- 0.6 mL/15 min; P < 0.05), and icv angiotensin II (2.2 +/- 0.8 vs saline: 10.4 +/- 2.0 mL/2 h; P < 0.05), without changing icv carbachol-induced water intake, sodium depletion-induced 1.8% NaCl intake and food deprivation-induced food intake. These data suggest that central ATP, acting on purinergic P2 receptors, reduces water intake induced by intracellular and extracellular dehydration.
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Affiliation(s)
- D R G de Faria
- Departamento de Fisiologia e Patologia, Faculdade de Odontologia de Araraquara, Universidade Estadual Paulista, Araraquara, SP, Brazil
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de Andrade CA, de Andrade GM, De Paula PM, De Luca LA, Menani JV. Involvement of central α1-adrenoceptors on renal responses to central moxonidine and α-methylnoradrenaline. Eur J Pharmacol 2009; 607:60-7. [DOI: 10.1016/j.ejphar.2009.01.039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Moreira TS, Takakura AC, Menani JV, Colombari E. Involvement of central α1- and α2-adrenoceptors on cardiovascular responses to moxonidine. Eur J Pharmacol 2007; 563:164-71. [PMID: 17382316 DOI: 10.1016/j.ejphar.2007.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2006] [Revised: 01/29/2007] [Accepted: 02/01/2007] [Indexed: 02/07/2023]
Abstract
In the present study we compared the effects produced by moxonidine (alpha2-adrenoceptor/imidazoline agonist) injected into the 4th cerebral ventricle and into the lateral cerebral ventricle on mean arterial pressure, heart rate and on renal, mesenteric and hindquarter vascular resistances, as well as the possible action of moxonidine on central alpha1- or alpha2-adrenoceptors to produce cardiovascular responses. Male Holtzman rats (n=7-8) anesthetized with urethane (0.5 g/kg, intravenously-i.v.) and alpha-chloralose (60 mg/kg, i.v.) were used. Moxonidine (5, 10 and 20 nmol) injected into the 4th ventricle reduced arterial pressure (-19+/-5, -30+/-7 and -43+/-8 mmHg vs. vehicle: 2+/-4 mmHg), heart rate (-10+/-6, -16+/-7 and -27+/-9 beats per minute-bpm, vs. vehicle: 4+/-5 bpm), and renal, mesenteric and hindquarter vascular resistances. Moxonidine (5, 10 and 20 nmol) into the lateral ventricle only reduced renal vascular resistance (-77+/-17%, -85+/-13%, -89+/-10% vs. vehicle: 3+/-4%), without changes on arterial pressure, heart rate and mesenteric and hindquarter vascular resistances. Pre-treatment with the selective alpha2-adrenoceptor antagonist yohimbine (80, 160 and 320 nmol) injected into the 4th ventricle attenuated the hypotension (-32+/-5, -25+/-4 and -12+/-6 mmHg), bradycardia (-26+/-11, -23+/-5 and -11+/-6 bpm) and the reduction in renal, mesenteric and hindquarter vascular resistances produced by moxonidine (20 nmol) into the 4th ventricle. Pre-treatment with yohimbine (320 nmol) into the lateral ventricle did not change the renal vasodilation produced by moxonidine (20 nmol) into the lateral ventricle. The alpha1-adrenoceptor antagonist prazosin (320 nmol) injected into the 4th ventricle did not affect the cardiovascular effects of moxonidine. However, prazosin (80, 160 and 320 nmol) into the lateral ventricle abolished the renal vasodilation (-17+/-4, -6+/-9 and 2+/-11%) produced by moxonidine. The results indicate that the decrease in renal vascular resistance due to moxonidine action in the forebrain is mediated by alpha1-adrenoceptors, while the cardiovascular effects produced by moxonidine acting in the brainstem depend at least partially on the activation of alpha2-adrenoceptors.
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Affiliation(s)
- Thiago S Moreira
- Department of Physiology, Universidade Federal de São Paulo, Escola Paulista de Medicina, Rua Botucatu, 862, 04023-060, São Paulo, SP, Brazil.
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Andrade CAF, De Luca LA, Colombari DSA, Menani JV. Alpha2-adrenergic activation in the lateral parabrachial nucleus induces NaCl intake under conditions of systemic hyperosmolarity. Neuroscience 2006; 142:21-8. [PMID: 16890365 DOI: 10.1016/j.neuroscience.2006.04.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2006] [Revised: 04/10/2006] [Accepted: 04/13/2006] [Indexed: 10/24/2022]
Abstract
The inhibition of sodium intake by increased plasma osmolarity may depend on inhibitory mechanisms present in the lateral parabrachial nucleus. Activation of alpha(2)-adrenergic receptors in the lateral parabrachial nucleus is suggested to deactivate inhibitory mechanisms present in this area increasing fluid depletion-induced 0.3 M NaCl intake. Considering the possibility that lateral parabrachial nucleus inhibitory mechanisms are activated and restrain sodium intake in animals with increased plasma osmolarity, in the present study we investigated the effects on water and 0.3 M NaCl intake produced by the activation of alpha(2)-adrenergic receptors in the lateral parabrachial nucleus in rats with increased plasma osmolarity. Male Holtzman rats with stainless steel cannulas implanted bilaterally into the lateral parabrachial nucleus were used. One hour after intragastric 2 M NaCl load (2 ml), bilateral injections of moxonidine (alpha(2)-adrenergic/imidazoline receptor agonist, 0.5 nmol/0.2 microl, n=10) into the lateral parabrachial nucleus induced a strong ingestion of 0.3 M NaCl intake (19.1+/-5.5 ml/2 h vs. vehicle: 1.8+/-0.6 ml/2 h), without changing water intake (15.8+/-3.0 ml/2 h vs. vehicle: 9.3+/-2.0 ml/2 h). However, moxonidine into the lateral parabrachial nucleus in satiated rats not treated with 2 M NaCl produced no change on 0.3 M NaCl intake. The pre-treatment with RX 821002 (alpha(2)-adrenergic receptor antagonist, 20 nmol/0.2 microl) into the lateral parabrachial nucleus almost abolished the effects of moxonidine on 0.3 M NaCl intake (4.7+/-3.4 ml/2 h). The present results suggest that alpha(2)-adrenergic receptor activation in the lateral parabrachial nucleus blocks inhibitory mechanisms, thereby allowing ingestion of hypertonic NaCl under conditions of extracellular hyperosmolarity. We suggest that during cell dehydration, circuits subserving sodium appetite are activated, but at the same time strongly inhibited through the lateral parabrachial nucleus.
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Affiliation(s)
- C A F Andrade
- Department of Physiology and Pathology, School of Dentistry, Universidade Estadual Paulista, Rua Humaitá 1680, Araraquara, SP 14801-903, Brazil
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Andrade CAF, Barbosa SP, De Luca LA, Menani JV. Activation of α2-adrenergic receptors into the lateral parabrachial nucleus enhances NaCl intake in rats. Neuroscience 2004; 129:25-34. [PMID: 15489025 DOI: 10.1016/j.neuroscience.2004.07.042] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/22/2004] [Indexed: 11/24/2022]
Abstract
Water and NaCl intake is strongly inhibited by the activation of alpha(2)-adrenergic receptors with clonidine or moxonidine (alpha(2)-adrenergic/imidazoline agonists) injected peripherally or into the forebrain and by serotonin and cholecystokinin in the lateral parabrachial nucleus (LPBN). Considering that alpha(2)-adrenergic receptors exist in the LPBN and the similar origin of serotonergic and adrenergic afferent pathways to the LPBN, in this study we investigated the effects of bilateral injections of moxonidine alone or combined with RX 821002 (alpha(2)-adrenergic antagonist) into the LPBN on 1.8% NaCl and water intake induced by the treatment with s.c. furosemide (10mg/kg)+captopril (5 mg/kg). Additionally, we investigated if moxonidine into the LPBN would modify furosemide+captopril-induced c-fos expression in the forebrain. Male Holtzman rats with cannulas implanted bilaterally in the LPBN were used. Contrary to forebrain injections, bilateral LPBN injections of moxonidine (0.1, 0.5 and 1 nmol/0.2 microl) strongly increased furosemide+captopril-induced 1.8% NaCl intake (16.6+/-2.7, 44.5+/-3.2 and 44.5+/-4.3 ml/2 h, respectively, vs. vehicle: 6.9+/-1.5 ml/2 h). Only the high dose of moxonidine increased water intake (23.3+/-3.8 ml/2 h, vs. vehicle: 12.1+/-2.6 ml/2 h). Prior injections of RX 821002 (10 and 20 nmol/0.2 microl) abolished the effect of moxonidine (0.5 nmol) on 1.8% NaCl intake. Moxonidine into the LPBN did not modify furosemide+captopril-induced c-fos expression in forebrain areas related to the control of fluid-electrolyte balance. The results show that the activation of LPBN alpha(2)-adrenergic receptors enhances furosemide+captopril-induced 1.8% NaCl and water intake. This enhancement was not related to prior alteration in the activity of forebrain areas as suggested by c-fos expression. Previous and present results indicate opposite roles for alpha(2)-adrenergic receptors in the control of sodium and water intake according to their distribution in the rat brain.
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Affiliation(s)
- C A F Andrade
- Department of Physiology and Pathology, School of Dentistry, Paulista State University (UNESP), Rua Humaitá, 1680, 14801-903 Araraquara, São Paulo, Brazil
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Moreira TS, Takakura ACT, Colombari E, De Luca LA, Renzi A, Menani JV. Central moxonidine on salivary gland blood flow and cardiovascular responses to pilocarpine. Brain Res 2003; 987:155-63. [PMID: 14499959 DOI: 10.1016/s0006-8993(03)03322-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Peripheral treatment with the cholinergic agonist pilocarpine induces intense salivation that is inhibited by central injections of the alpha2-adrenergic/imidazoline receptor agonist moxonidine. Salivary gland blood flow controlled by sympathetic and parasympathetic systems may affect salivation. We investigated the changes in mean arterial pressure (MAP) and in the vascular resistance in the submandibular/sublingual gland (SSG) artery, superior mesenteric (SM) artery and low abdominal aorta (hindlimb) in rats treated with intraperitoneal (i.p.) pilocarpine alone or combined with intracerebroventricular (i.c.v.) moxonidine. Male Holtzman rats with stainless steel cannula implanted into lateral ventricle (LV) and anesthetized with urethane were used. Pilocarpine (4 micromol/kg of body weight) i.p. reduced SSG vascular resistance (-50+/-13% vs. vehicle: 5+/-3%). Pilocarpine i.p. also increased mesenteric vascular resistance (15+/-5% vs. vehicle: 2+/-3%) and MAP (16+/-3 mmHg, vs. vehicle: 2+/-3 mmHg). Moxonidine (20 nmol) i.c.v. increased SSG vascular resistance (88+/-12% vs. vehicle: 7+/-4%). When injected 15 min following i.c.v. moxonidine, pilocarpine i.p. produced no change on SSG vascular resistance. Pilocarpine-induced pressor responses and increase in mesenteric vascular resistance were not modified by i.c.v. moxonidine. The treatments produced no change in heart rate (HR) and hindlimb vascular resistance. The results show that (1) i.p. pilocarpine increases mesenteric vascular resistance and MAP and reduces salivary gland vascular resistance and (2) central moxonidine increases salivary gland vascular resistance and impairs pilocarpine-induced salivary gland vasodilatation. Therefore, the increase in salivary gland vascular resistance may play a role in the anti-salivatory response to central moxonidine.
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Affiliation(s)
- Thiago Santos Moreira
- Departamento de Fisiologia e Patologia, Faculdade de Odontologia, Universidade Estadual Paulista, UNESP, Rua Humaitá, 1680, 14801-903, Araraquara, SP, Brazil
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12
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Abstract
Central injections of the alpha(2) adrenergic/imidazoline receptor agonist moxonidine inhibit water and NaCl intake in rats. In the present study, we investigated the possible involvement of central alpha(2) adrenergic receptors on the inhibitory effect of moxonidine in 0.3 M NaCl intake induced by 24 h sodium depletion. Male Holtzman rats with stainless-steel cannulas implanted into the lateral ventricle (LV) were used. Sodium depletion was produced by the treatment with the diuretic furosemide (20 mg/kg of body weight) injected subcutaneously +24 h of sodium-deficient diet. Intracerebroventricular (icv) injections of moxonidine (20 nmol/1 microl) reduced sodium depletion-induced 0.3 M NaCl intake (6.6+/-1.9 ml/120 min vs. vehicle: 12.7+/-1.7 ml/120 min). Pre-treatment with the alpha(2) adrenoreceptor antagonists RX 821002 (80 nmol/1 microl), SK&F 86466 (640 nmol/1 microl) and yohimbine (320 nmol/3 microl) injected icv abolished the inhibitory effect of icv moxonidine on sodium depletion-induced 0.3 M NaCl intake (13.3+/-1.4, 15.7+/-1.7 and 11.8+/-2.2 ml/120 min, respectively). The results show that the activation of alpha(2) adrenoreceptors is essential for the inhibitory effect of central moxonidine on sodium depletion-induced NaCl intake.
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Affiliation(s)
- Lisandra Brandino de Oliveira
- Department of Physiology and Pathology, School of Dentistry, Paulista State University, UNESP, Rua Humaitá, 1680 Araraquara, SP, Brazil
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Sugawara AM, Miguel TT, Pereira DT, Menani JV, De Luca LA. Effects of central imidazolinergic and alpha2-adrenergic activation on water intake. Braz J Med Biol Res 2001; 34:1185-90. [PMID: 11514843 DOI: 10.1590/s0100-879x2001000900012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Non-adrenergic ligands that bind to imidazoline receptors (I-R), a selective ligand that binds to alpha2-adrenoceptors (alpha2-AR) and mixed ligands that bind to both receptors were tested for their action on water intake behavior of 24-h water-deprived rats. All drugs were injected into the third cerebral ventricle. Except for agmatine (80 nmol), mixed ligands binding to I-R/alpha2-AR such as guanabenz (40 nmol) and UK 14304 (20 nmol) inhibited water intake by 65% and up to 95%, respectively. The selective non-imidazoline alpha2-AR agonist, alpha-methylnoradrenaline, produced inhibition of water intake similar to that obtained with guanabenz, but at higher doses (80 nmol). The non-adrenergic I-R ligands histamine (160 nmol, mixed histaminergic and imidazoline ligand) and imidazole-4-acetic acid (80 nmol, imidazoline ligand) did not alter water intake. The results show that selective, non-imidazoline alpha2-AR activation suppresses water intake, and suggest that the action on imidazoline sites by non-adrenergic ligands is not sufficient to inhibit water intake.
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Affiliation(s)
- A M Sugawara
- Departamento de Fisiologia e Patologia, Faculdade de Odontologia, Universidade Estadual Paulista, Araraquara, SP, Brasil
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