Cytokines and acute-phase serum proteins as markers of inflammatory regression during pulmonary tuberculosis treatment

Tuberculosis is still increasing and was declared a worldwide sanitary emergency by the World Health Organization (WHO) in 1995. Its control is difficult due to long treatment duration and lack of markers of treatment success or failure. Cytokines such as IFN-gamma and TNF-alpha, a central factor in immune response against Mycobacterium tuberculosis, are responsible for the interaction between T lymphocytes and the infected macrophage and are also produced during this interaction. As proinflammatory cytokines have a close relationship with mycobacteria clearance, in fact even preceding it, they could be used as markers for inflammatory activity and response to treatment. Proinflammatory cytokines act in the liver and stimulate a strong local and systemic acute-phase response as a result of homeostatic and physiological responses also induced by them. Acute-phase proteins produced by cytokine activity are useful diagnostic markers that could also be used to monitor treatment response as they can be serially quantified. The objective of this study was to evaluate IFN-gamma, TNF-alpha, IL-10 and TGF-beta production in supernatant of peripheral blood mononuclear cell (PBMC) and monocyte (MO) cultures, as well as serum acute-phase response through total protein, albumin, globulin, C-reactive protein (CRP), alpha-1-acid glycoprotein (AGP), and erythrocyte sedimentation rate (ESR) as regression markers of inflammatory response during pulmonary tuberculosis treatment. Twenty blood donors (G1) from the Blood Bank at Botucatu School of Medicine's University Hospital (BSM-UH) were evaluated once and 28 pulmonary tuberculosis patients (G2): 13 from BSM-UH and 15 from the Bauru State Health Secretariat. Patients were evaluated at three moments of treatment: before (M1), at three months (M2), and at the end (M3). Cytokines were determined in 20ml of peripheral blood (ELISA), with or without activation: lipopolysaccharide (LPS) for MO culture and phytohemagglutinin (PHA) for PBMC culture. Acute-phase protein behavior in G2 throughout treatment was: Globulins: M1> M2, M1> M3 (rho < 0.001); CRP: M1> M2> M3 (.< 0.001); AGP for men: M1> M2, M1> M3 (rho < 0.001); ESR for men: M1> M2, M1> M3 (rho < 0.0016) and for women: M1> M2 (.< 0.025). Comparison between cytokine levels found in supernatant of MO and PBMC cultures, with and without stimulus, in G1 and G2 during treatment showed: TNF-alpha (with/ without LPS) at M1: G2> G1; at M2: G2> G1 (rho < 0.001); (without LPS) at M3: G2> G1 (rho < 0.001), (with LPS) at M3: G2> G1 (rho < 0.028); IFN-. (with and without PHA) at M1: G2> G1; at M2: G2> G1 (rho < 0.001); IL-10 (with and without LPS) at M1: G2> G1; at M2: G2> G1; at M3: G2> G1 (rho < 0.001); TGF-beta (with and without LPS) at M1: G2> G1; at M2: G2> G1 (rho < 0.001), (without LPS) at M3: G2> G1 (rho < 0.001). In G2, all cytokines in supernatant of MO and PBMC cultures, with and without stimulus, showed: M1> M2> M3 (rho < 0.01). Levels of globulins, CRP, AGP, and ESR in patients with pulmonary tuberculosis before treatment (M1) were significantly higher than reference values, suggesting their use as diagnostic markers and indicators of treatment. The CRP decreasing values along treatment could be taken as a marker of the regression of inflammatory process and of response to treatment in patients with pulmonary tuberculosis.Regarding cytokines, there was significant increase in TNF-alpha, IFN-gamma, IL-10, and TGF-alpha levels before and at three months treatment, with and without stimulus; in TNF-a and IL-10 lvels, with and without stimulus, as well as in TGF-alpha levels without stimulus at six months. Patients had higher levels of all studied cytokines than controls before treatment, and these values decreased along treatment. In this study, pulmonary tuberculosis patients showed a Th0 cytokine profile before treatment, with the production of both Th1 (IFN-gamma) and Th2 (IL-10) cytokines, in addition to TNF-alpha inflammatory and TGF-alpha regulatory and fibrosis-inducer cytokines. At the end of treatment, all had evolved to Th2 profile, probably in an attempt to reduce the harmful effects of the proinflammatory activity of the Th1 cytokine profile and of the still above-normal levels of TNF-alpha. The high levels of TGF-alpha, also found in these patients, are related to its important role in the extracellular matrix deposition and fibrosis induction that characterize tuberculosis healing process. IFN-gamma was the only cytokine reaching normal levels at the end of treatment, which suggests its use as a marker of response to treatment.

Acupuntura: histórico, bases teóricas e sua aplicação em Medicina Veterinária

A acupuntura (AP) é uma técnica terapêutica empírica desenvolvida em uma cultura oriental e que utiliza pensamento mágico (linguagem pré-científica) em seu raciocínio. É uma terapia reflexa que utiliza a estimulação de pontos específicos do corpo com objetivo de atingir um efeito terapêutico ou homeostático. A AP preconiza que a saúde é dependente das funções psico-neuro-endócrinas, sob influência do código genético e de fatores extrínsecos como nutrição, hábitos de vida, clima, qualidade do ambiente, entre outros. O presente artigo faz uma breve revisão sobre a filosofia da AP, seus marcos históricos na China e no Ocidente, a história da AP veterinária no Brasil e no mundo. Também aborda a prática da AP, incluindo as formas de diagnóstico, a definição do protocolo de tratamento, os métodos de estimulação dos pontos, o agulhamento de animais, suas indicações, contra-indicações e reações adversas.

GABA(A) receptor activation in the lateral parabrachial nucleus induces water and hypertonic NaCl intake

Inhibitory serotonergic and cholecystokinergic mechanisms in the lateral parabrachial nucleus and central GABAergic mechanisms are involved in the regulation of water and NaCl intake. In the present study we investigated if the GABA(A) receptors in the lateral parabrachial nucleus are involved in the control of water, NaCl and food intake in rats. Male Holtzman rats with stainless steel cannulas implanted bilaterally into the lateral parabrachial nucleus were used. Bilateral injections of muscimol (0.2 nmol/0.2 mu l) into the lateral parabrachial nucleus strongly increased 0.3 M NaCl (20.3 +/- 7.2 vs. saline: 2.6 +/- 0.9 ml/180 min) without changing water intake induced by the treatment with the diuretic furosemide combined with low dose of the angiotensin converting enzyme inhibitor captopril s.c. In euhydrated and satiated rats, bilateral lateral parabrachial nucleus injections of muscimol (0.2 and 0.5 nmol/0.2 0) induced 0.3 M NaCl intake (12.1 +/- 6.5 and 32.5 +/- 7.3 ml/180 min, respectively, vs. saline: 0.4 +/- 0.2 ml/180 min) and water intake (5.2 +/- 2.0 and 7.6 +/- 2.8 ml/ 180 min, respectively, vs. saline: 0.8 +/- 0.4 ml/180 min), but no food intake (2 +/- 0.4 g/240 min vs. saline: 1 +/- 0.3 g/240 min). Bilateral lateral parabrachial nucleus injections of the GABAA antagonist bicuculline (1.6 nmol/0.2 mu l) abolished the effects of muscimol (0.5 nmol/0.2 mu l) on 0.3 M NaCl and water intake. Muscimol (0.5 nmol/0.2 mu l) into the lateral parabrachial nucleus also induced a slight ingestion of water (4.2 +/- 1.6 ml/240 min vs. saline: 1.1 +/- 0.3 ml/240 min) when only water was available, a long lasting (for at least 2 h) increase on mean arterial pressure (14 +/- 4 mm Hg, vs. saline: -1 +/- 1 mm Hg) and only a tendency to increase urinary volume and Na+ and K+ renal excretion. Therefore the activation of GABAA receptors in the lateral parabrachial nucleus induces strong NaCl intake, a small ingestion of water and pressor responses, without changes on food intake. (c) 2005 Published by Elsevier Ltd on behalf of IBRO.

GABAergic mechanisms of the lateral parabrachial nucleus on sodium appetite

GABAergic activation in the lateral parabrachial nucleus (LPBN) induces sodium and water intake in satiated and normovolemic rats. In the present study we investigated the effects of GABA(A) receptor activation in the LPBN on 0.3 M NaCl, water, 2% sucrose and food intake in rats submitted to sodium depletion (treatment with the diuretic furosemide subcutaneously + sodium deficient food for 24 h), 24 h food deprivation or 24 h water deprivation. Male Holtzman rats with bilateral stainless steel cannulas implanted into the LPBN were used. In sodium depleted rats, muscimol (GABA(A) receptor agonist, 0.5 nmol/0.2 mu/l), bilaterally injected into the LPBN, produced an inconsistent increase of water intake and two opposite effects on 0.3 M NaCl intake: an early inhibition (4.3 +/- 2.7 versus saline: 14.4 +/- 1.0 ml/15 min) and a late facilitation (37.6 +/- 2.7 versus saline: 21.1 +/- 0.9 ml/180 min). The pretreatment of the LPBN with bicuculline (GABA(A) receptor antagonist, 1.6 nmol) abolished these effects of muscimol. Muscimol into the LPBN also reduced food deprivation-induced food intake in the first 30 min of test (1.7 +/- 0.6 g versus saline: 4.1 +/- 0.6 g), without changing water deprivation-induced water intake or 2% sucrose intake in sodium depleted rats. Therefore, although GABAA receptors in the LPBN are not tonically involved in the control of sodium depletion-induced sodium intake, GABAA receptor activation in the LPBN produces an early inhibition and a late facilitation of sodium depletion-induced sodium intake. GABAA activation in the LPBN also inhibits food intake, while it consistently increases only sodium intake and not water, food or sucrose intake. (c) 2007 Elsevier B.V. All rights reserved.

Sodium intake by hyperosmotic rats treated with a GABA(A) receptor agonist into the lateral parabrachial nucleus

Inhibitory mechanisms in the lateral parabrachial nucleus (LPBN) and central GABAergic mechanisms are involved in the regulation of water and NaCl intake. Besides increasing fluid depletion-induced sodium intake, the activation of GABA(A) receptors with muscimol into the LPBN also induces ingestion of 0.3 M NaCl in normonatremic, euhydrated rats. It has been suggested that inhibitory mechanisms activated by osmotic signals are blocked by GABAA receptor activation in the LPBN, thereby increasing hypertonic NaCl intake. Therefore, in the present study we investigated the effects of muscimol injected into the LPBN on water and 0.3 M NaCl intake in hyperosmotic cell-dehydrated rats (rats treated with an intragastric load of 2 M NaCl). Male Wistar rats with stainless steel cannulas implanted bilaterally into the LPBN were used. In euhydrated rats, muscimol (0.5 nmol/0.2 mu l), bilaterally injected into the LPBN, induced ingestion of 0.3 M NaCl (24.6 +/- 7.9 vs. vehicle: 0.5 +/- 0.3 ml/180 min) and water (6.3 +/- 2.1 vs. vehicle: 0.5 +/- 0.3 ml/180 min). One hour after intragastric 2 M NaCl load (2 ml), bilateral injections of muscimol into the LPBN also induced 0.3 M NaCl intake (22.1 +/- 5.2 vs. vehicle: 0.9 +/- 0.8 ml/210 min) and water intake (16.5 +/- 3.6 vs. vehicle: 7.8 +/- 1.8 ml/210 min). The GABAA antagonist bicuculline (0.4 nmol/0.2 mu l) into the LPBN reduced the effect of muscimol on 0.3 M NaCl intake (7.1 +/- 2.1 ml/210 min). Therefore, the activation of GABAA receptors in the LPBN induces ingestion of 0.3 M NaCl by hyperosmotic cell-dehydrated rats, suggesting that plasma levels of renin or osmolarity do not affect sodium intake after the blockade of LPBN inhibitory mechanisms with muscimol. (c) 2007 Elsevier B.V. All rights reserved.

Natriorexigenic effect of baclofen is reduced by AT(1) receptor blockade in the lateral parabrachial nucleus

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Involvement of forebrain imidazoline and alpha(2)-adrenergic receptors in the antidipsogenic response to moxonidine

We investigated the participation of central alpha(2)-adrenoceptors and imidazoline receptors in the inhibition of water deprivation-induced water intake in rats. The alpha(2)-adrenoceptor and imidazoline antagonist idazoxan (320 nmol), but not the alpha(2)-adrenoceptor antagonist yohimbine, abolished the antidipsogenic effect of moxonidine (alpha(2)-adrenoceptor and imidazoline agonist, 20 nmol) microinjected into the medial septal area. Yohimbine abolished the antidipsogenic effect of moxonidine intracerebroventricularly. Therefore, central moxonidine may inhibit water intake acting independently on both imidazoline receptors and alpha(2)-adrenoceptors at different forebrain sites.

Activation of alpha(2)-adrenergic receptors into the lateral parabrachial nucleus enhances NaCl intake in rats

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 (10 mg/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 mul) 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 mu1) 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 a2-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. (C) 2004 IBRO. Published by Elsevier Ltd. All rights reserved.

5-HT2 and 5-HT3 receptors in the lateral parabrachial nucleus mediate opposite effects on sodium intake

The present study investigated the role of several 5-HT receptor subtypes in the lateral parabrachial nucleus (LPBN) in the control of sodium appetite (i.e. NaCl consumption). Male Holtzman rats had cannulas implanted bilaterally into the LPBN for the injection of 5-HT receptor agonists and antagonists in conjunction with either acute fluid depletion or 24-h sodium depletion. Following these treatments, access to 0.3 M NaCl was provided and the intakes of saline and water were measured for the next 2 h. Bilateral injections of the 5-HT2A receptor antagonist, ketanserin or the 5-HT2C receptor antagonist, mianserin into the LPBN increased 0.3 M NaCl intake without affecting water intake induced by acute fluid-depletion. Bilateral injections of the 5-HT2B receptor agonist, BW723C86 hydrochloride, had no effect on 0.3 M NaCl or water intake under these conditions. Treatment of the LPBN with the 5-HT2B/2C receptor agonist, 2-(2-methyl-4-clorophenoxy) propanoic acid (mCPP) caused dose-related reductions in 0.3 M NaCl intake after 24 h sodium depletion. The effects of mCPP were prevented by pretreating the LPBN with the 5-HT2B/2C receptor antagonist, SDZSER082. Activation of 5-HT3 receptors by the receptor agonist, 1-phenylbiguanicle (PBG) caused dose-related increases in 0.3 M NaCl intake. Pretreatment of the LPBN with the 5-HT3 receptor antagonist, 1-methyl-N-[8-methyl-8-azabicyclo (3.2.1)-oct-3-yl]-1H-indazole-3-carboxamide (LY-278,584) abolished the effects of PBG, but LY-278,584 had no effects on sodium or water intake when injected by itself. PBG injected into the LPBN did not alter intake of palatable 0.06 M sucrose in fluid replete rats. The results suggest that activation of the 5-HT2A and 5-HT2C receptor subtypes inhibits sodium ingestion. In contrast, activation of the 5-HT3 receptor subtype increases sodium ingestion. Therefore, multiple serotonergic receptor subtypes in the LPBN are implicated in the control of sodium intake, sometimes by mediating opposite effects of 5-HT. The results provide new information concerning the control of sodium intake by LPBN mechanisms. (C) 2007 IBRO. Published by Elsevier Ltd. All rights reserved.

Brain serotonin blockade and paradoxical salt intake in rats

Serotonin antagonism in the lateral parabrachial nucleus (LPBN) enhances sodium appetite induced by hypovolaemia and angiotensin-mineralocorticoid activation, but produces no sodium intake in euhydrated animals. In the present work, male adult rats (n=21) that received bilateral injections of the serotonergic antagonist methysergide (4 mug/ 0.2 mul) into the LPBN combined to intragastric load of 2 M NaCl (2 ml/rat), ingested hypertonic NaCl (ingestion of 4.3+/-1.6 ml/2 h of 0.3 M NaCl versus vehicle into LPBN: 0.2+/-0.2 ml/2 h, P<0.05). Methysergide- and vehicle-treated animals also ingested water (9.5+/-0.7 and 7.2+/-0.5 ml/2 h, respectively, P>0.05) as expected from the state of cell dehydration produced by the load. Ingestion of water (11.0+/-1.2 ml/2 h), and of 0.3 M NaCl (1.1+/-0.7 ml/2 h) were not altered by methysergide in NaCl loaded rats with misplaced LPBN injections (n=15). The ingestion of hypertonic NaCl by rats with serotonergic blockade in the LPBN suggests that the circuits subserving sodium appetite are activated, but at the same time strongly inhibited through the LPBN, during cell dehydration. (C) 2003 IBRO. Published by Elsevier Ltd. All rights reserved.

Serotonergic mechanism of the lateral parabrachial nucleus and relaxin-induced sodium intake

It has been shown that central or peripheral injections of the peptide relaxin induces water intake, not sodium intake in rats. Important inhibitory mechanisms involving serotonin and other neurotransmitters in the control of water and NaCl intake have been demonstrated in the lateral parabrachial nucleus (LPBN). In the present Study, we investigated the effects of bilateral injections of methysergide (serotonergic receptor antagonist) into the LPBN on intracerebroventricular (i.c.v.) relaxin-induced water and NaCl intake in rats. Additionally, the effect of the blockade of central angiotensin AT(1) receptors with i.c.v. losartan on relaxin-induced water and NaCl intake in rats treated with methysergide into the LPBN was also investigated. Male Holtzman rats with cannulas implanted into the lateral ventricle (LV) and bilaterally in the LPBN were used. Intracerebroventricular injections of relaxin (500 ng/l mul) induced water intake (5.1+/-0.7 ml/120 min), but not significant 1.8% NaCl intake (0.5+/-0.4 ml/120 min). Bilateral injections of methysergide (4 mug/0.2 mul) into the LPBN strongly stimulated relaxin-induced 1.8% NaCl intake (34.5+/-10.9 ml/120 min) and slightly increased water intake (10.5+/-4.9 ml/120 min). The pretreatment with i.c.v. losartan (100 mug/l mul) abolished the effects of i.c.v. relaxin combined with LPBN methysergide on 1.8% NaCI intake (0.5+/-0.4 ml/120 min). Losartan (100 mug/l mul) also abolished relaxin-induced water intake in rats injected with methysergide into the LPBN (1.6+/-0.8 ml/120 min) or not (0.5+/-0.3 ml/120 min). Losartan (50 mug/l mul) partially reduced the effects of relaxin. The results show that central relaxin interacting with central angiotensinergic mechanisms induces NaCl intake after the blockade of LPBN serotonergic mechanisms. (C) 2004 Elsevier B.V. All rights reserved.

Alpha(2)-adrenergic activation in the lateral parabrachial nucleus induces NaCi intake under conditions of systemic hyperosmolarity

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 mu l, 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 mu l) 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. (c) 2006 IBRO. Published by Elsevier Ltd. All rights reserved.

Effects of V-1 and angiotensin receptor subtypes of the paraventricular nucleus on the water intake induced by vasopressin injected into the lateral septal area

In this study, we investigated the influence of d(CH2)(5)-Tyr (Me)-AVP (AAVP) an antagonist of V-1 receptors of arginine(8)-vasopressin (AVP) and the effects of losartan and CGP42112A (selective ligands of the AT, and AT, angiotensin receptors, respectively) injections into the paraventricular nucleus (PVN) on the thirst effects of AVP stimulation of the lateral septal area (LSA). AVP injection into the LSA increased the water intake in a dose-dependent manner. AAVP injected into the PVN produced a dose-dependent reduction of the drinking responses elicited by LSA administration of AVP. Both the AT(1) and AT(2) ligands administered into the PVN elicited a concentration-dependent inhibition in the water intake induced by AVP injected into the LSA, but losartan was more effective than CGP42112A the increase in the AVP response. These results indicate that LSA dipsogenic effects induced by AVP are mediated primarily by PVN AT(1) receptors. However, doses of losartan were more effective when combined with CGP42112A than when given alone, suggesting that the thirst induced by AVP injections into LSA may involve activation of multiple angiotensin II (ANG II) receptor subtypes. These results also suggests that facilitatory effects of AVP on water intake into the LSA are mediated through the activation of V-receptors and that the inhibitory effect requires V-receptors. Based on the present findings, we suggest that the administration of AVP into the LSA may play a role in the PVN control of water control. (C) 2003 Elsevier B.V. All rights reserved.

Activation of serotonergic 5-HT1A receptors in the lateral parabrachial nucleus increases NaCl intake

Previous studies using non-specific serotonergic agonists and antagonists have shown the importance of serotonergic inhibitory mechanisms in the lateral parabrachial nucleus (LPBN) for controlling sodium and water intake. In the present study, we investigated whether the serotonergic 5-HTIA receptor subtype in the LPBN participates in this control. Male Holtzman rats had cannulas implanted bilaterally into the LPBN. Bilateral injections of the 5-HTIA receptor agonist, 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT, 0.1, 1.25, and 2.5 mu g/ 0.2 mu l), into the LPBN enhanced 0.3 M NaCl and water intake of rats injected subcutaneously with the diuretic furosemide (10 mg/kg bw) and a low dose of the angiotensin-converting enzyme inhibitor, captopril (5 mg/kg bw). The increase in NaCl intake produced by 8-OH-DPAT injections was reduced in dose-related manner by pre-treating the LPBN with the selective 5-HTIA serotonergic antagonist, WAY-100635 (WAY, I and 2 mu g/0.2 mu l). In contrast, WAY did not affect water intake produced by 8-OH-DPAT. WAY-100635 injected alone into the LPBN had no effect on NaCl ingestion. Injections of 8-OH-DAPT (0.1 mu g/0.2 mu l) into the LPBN also increased 0.3 M NaCl intake induced by 24-h sodium depletion (furosemide, 20 mg/kg bw plus 24 h of sodium-free diet). Serotonin (5-HT, 20 mu g/0.2 mu l) injected alone or combined with 8-OH-DPAT into the LPBN reduced 24-h sodium depletion-induced 0.3 M NaCl intake. Therefore, the activation of serotonergic 5-HTIA receptors in the LPBN increases stimulated hypertonic NaCl and water intake, while 5-HT injections into the LPBN reduce NaCl intake and prevent the effects of serotonergic 5-HTIA receptor activation. (c) 2005 Elsevier B.V. All rights reserved.

Water deprivation-induced sodium appetite: humoral and cardiovascular mediators and immediate early genes

Adult rats deprived of water for 24-30 h were allowed to rehydrate by ingesting only water for 1-2 h. Rats were then given access to both water and 1.8% NaCl. This procedure induced a sodium appetite defined by the operational criteria of a significant increase in 1.8% NaCl intake (3.8 +/- 0.8 ml/2 h; n = 6). Expression of Fos (as assessed by immunohistochemistry) was increased in the organum vasculosum of the lamina terminalis (OVLT), median preoptic nucleus (MnPO), subfornical organ (SFO), and supraoptic nucleus (SON) after water deprivation. After rehydration with water but before consumption of 1.8% NaCl, Fos expression in the SON disappeared and was partially reduced in the OVLT and MnPO. However, Fos expression did not change in the SFO. Water deprivation also 1) increased plasma renin activity (PRA), osmolality, and plasma Na+; 2) decreased blood volume; and 3) reduced total body Na+; but 4) did not alter arterial blood pressure. Rehydration with water alone caused only plasma osmolality and plasma Na+ concentration to revert to euhydrated levels. The changes in Fos expression and PRA are consistent with a proposed role for ANG II in the control of the sodium appetite produced by water deprivation followed by rehydration with only water.