Role of hippocampal nitrergic neurotransmission in behavioral and cardiovascular dysfunctions evoked by chronic social stress.

Increased nitric oxide (NO) levels have been identified in the hippocampus of animals subjected to social isolation. However, a role of this change in behavioral and physiological changes evoked by isolation has never been evaluated. Thus, this study investigated the involvement of nitrergic neurotransmission acting via the neuronal isoform of nitric oxide synthase (nNOS) within the dorsal hippocampus in behavioral and cardiovascular changes in isolated reared rats. For this, male rats were isolated from weaning at 21 days postnatal for 40 days. We identified that social isolation increased hippocampal NO formation and nNOS expression. Besides, anxiogenic- and depressive-like effect identified in isolated animals were not affected by intra-hippocampal microinjection of either the NO scavenger carboxy-PTIO or the selective nNOS inhibitor Nω-Propyl-l-arginine (NPLA). Isolation also increased basal arterial pressure, impaired the baroreflex function and decreased the tachycardia to restraint stress. The effects in restraint-evoked tachycardia were inhibited by hippocampal treatment with either carboxy-PTIO or NPLA. Intra-hippocampal administration of either carboxy-PTIO or NPLA also enhanced the pressor response to restraint in isolated, but not in control animals. Taken together, these findings indicate that increased NO release within the dorsal hippocampus is involved in impairment of cardiovascular responses to a novel stressor, but not in behavioral effects and baroreflex changes, evoked by social isolation. Furthermore, exposure to this stressor evokes the emergence of an inhibitory role of hippocampal nNOS activation in cardiovascular changes to a novel stressor, which might constitute a prominent adaptive response.

Differential roles of hippocampal nNOS and iNOS in the control of baroreflex function in conscious rats.

The baroreflex is a prominent moment-to-moment mechanism regulating the blood pressure. The hippocampus is a limbic structure in which has been pointed out as part of central network regulating baroreflex. However, the local neurochemical mechanisms involved in control of baroreflex function are not completely understood. Thus, this study aimed to investigate the involvement of nitrergic neurotransmission present in the dorsal hippocampus in baroreflex control of heart rate in conscious rats. For this, we evaluated the effect of bilateral microinjection into the dorsal hippocampus of either the nitric oxide (NO) scavenger carboxy-PTIO, the selective neuronal nitric oxide synthase (nNOS) inhibitor Nω-Propyl-l-arginine (NPLA) or the selective inducible nitric oxide synthase (iNOS) inhibitor 1400 W in bradycardia evoked by blood pressure increases in response to intravenous infusion of phenylephrine, and tachycardia caused by blood pressure decreases evoked by intravenous infusion of sodium nitroprusside. Bilateral microinjection of carboxy-PTIO into the dorsal hippocampus decreased the baroreflex tachycardic response without affecting the reflex bradycardia. Hippocampus treatment with NPLA increased the baroreflex bradycardia gain without affecting the reflex tachycardia. Bilateral hippocampal treatment with 1400 W decreased the reflex tachycardia and increased the baroreflex bradycardic response. Overall, these findings provide evidence that hippocampal nitrergic mechanisms acting in a NOS isoform-specific manner plays a prominent role in control of baroreflex function. Indeed, the results indicate that nNOS and iNOS exerts an inhibitory influence on reflex bradycardia, whereas iNOS mediates the reflex tachycardia.

Antagonism of Bacteria from Dog Dental Plaque against Human Cariogenic Bacteria.

Dental caries are a process of demineralization and destruction of human teeth. They originate through many factors and are associated with biofilm formation, which consists of bacteria adhered to the teeth that form a structurally and functionally organized mass called dental plaque. Both the presence of Streptococcus mutans and the frequent consumption of sucrose correlate with a higher prevalence of caries in humans. In dogs, however, the incidence of this disease is low, due to factors such as differences in dental microbiota and/or their low consumption of sucrose. This work evaluated the antagonism of bacteria from dog's dental plaque against S. mutans, for the identification of producing strains of biotechnological products for use in preventing caries. This study used 95 bacterial isolates of canine dental plaque from the Veterinary Department at the Federal University of Viçosa, Minas Gerais, Brazil. A spot-on-the-lawn method was performed using Brain Heart Infusion agar with catalase for an initial identification of the antagonistic activity. Additional tests were conducted on the isolates classified as antagonists for confirmation of the activity, using modified Mann-Rogosa-Sharpe medium containing low dextrose concentration. These isolates were incubated at 37°C for 24 hours in anaerobiosis. The peptide nature of inhibition was evaluated using the following proteinases: proteinase K from Tritirachium album, bovine pancreatic trypsin, and type XII-A α-amylase from Bacillus licheniformis. In the initial identification of those strains exhibiting antimicrobial activity, 14 were classified as antagonists. One of the isolates (Bacillus sp.) indicated bacteriocinogenic activity, with a deformed inhibition halo on S. mutans by the addition of trypsin. These results suggest that this bacterial isolate may be applicable to biotechnological use to combat the main etiological agent of caries in humans. Further studies are needed to evaluate the bacteriocinogenic nature of the antimicrobial activities of the other 13 antagonistic bacterial isolates.

Nitric oxide-cGMP-PKG signaling in the bed nucleus of the stria terminalis modulates the cardiovascular responses to stress in male rats.

The bed nucleus of the stria terminalis (BNST) constitutes an important component of neural substrates of physiological and behavioral responses to aversive stimuli, and it has been implicated on cardiovascular responses evoked by stress. Nevertheless, the local neurochemical mechanisms involved in BNST control of cardiovascular responses during aversive threats are still poorly understood. Thus, the aim of the present study was to assess the involvement of activation in the BNST of the neuronal isoform of the enzyme nitric oxide synthase (nNOS), as well as of signaling mechanisms related to nitric oxide effects such as soluble guanylate cyclase (sGC) and protein kinase G (PKG) on cardiovascular responses induced by an acute session of restraint stress in male rats. We observed that bilateral microinjection of either the nonselective NOS inhibitor Nω-Nitro-L-arginine methyl ester (L-NAME), the selective nNOS inhibitor Nω-Propyl-L-arginine (NPLA) or the sGC inhibitor 1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) into the BNST enhanced the tachycardic response and decreased the drop in tail cutaneous temperature evoked by acute restraint stress, but without affecting the increase on blood pressure. Bilateral BNST treatment with the selective PKG inhibitor KT5823 also facilitated the heart rate increase and decreased the drop in cutaneous temperature, in addition to enhancing the blood pressure increase. Taken together, these results provide evidence that NO released from nNOS and activation of sGC and PKG within the BNST play an inhibitory influence on tachycardia to stress, whereas this signaling mechanism mediates the sympathetic-mediated cutaneous vasoconstriction.

A relação entre ciclo menstrual e gengivite / The relationship between the menstrual cycle and gingivitis

A gengivite é uma doença inflamatória que interfere nos tecidos de suporte dos dentes. Inicia-se pelo acúmulo da placa bacteriana sobre as faces dentárias e a margem gengival, promovendo a liberação de produtos tóxicos que são efeitos da combinação da bactéria e do hospedeiro. Há indícios de que os hormônios sexuais, principalmente os esteroidais, que estão presentes no ciclo menstrual, apresentem efeitos sobre a saúde periodontal, causando impactos diretos na inflamação gengival e em possíveis alterações de substâncias no fluido gengival. Para tanto, realizou-se uma pesquisa de campo com o intuito de validar a relação entre o ciclo menstrual e a gengivite e seus possíveis diagnósticos frente aos hormônios sexuais que se apresentam de forma tão relevante. OBJETIVO: O objetivo do presente trabalho é verificar através de uma pesquisa de campo, se durante o ciclo menstrual, as alterações hormonais causadas neste período têm capacidade de gerar alterações nos tecidos gengivais. METODOLOGIA: Trata-se de uma pesquisa de campo, realizada por meio de artigos indexados na base científica SciELO e avaliação clínica e sondagem da gengiva de 20 voluntárias durante o período pré-mentrual, menstrual e período pós-mentrual de cada uma.(AU)

Gingivitis is an inflammatory disease that affects the supporting tissues of the teeth. It begins by the accumulation of bacterial plaque on the dental faces and the gingival margin, promoting the release of toxic products that are effects of the combination of bacteria and the host. There are indications that the sex hormones, especially the steroidal ones, that are present in the menstrual cycle, have effects on the periodontal health, causing direct impacts on gingival inflammation and possible alterations of substances in the gingival fluid. Therefore, a field research was carried out with the purpose of validating the relationship between the menstrual cycle and gingivitis and its possible diagnoses against the sex hormones that present themselves in such a relevant way. OBJECTIVE: The objective of the present study is to verify through a field survey whether, during the menstrual cycle, the hormonal changes caused in this period have the capacity to generate alterations in the gingival tissues. METHODOLOGY: This is a field study, carried out by means of articles indexed in SciELO scientific basis and clinical evaluation and gingival probing of 20 volunteers during the pre-mentual period, menstrual period and post-mentual period of each.(AU)

CRF1 and CRF2 receptors in the bed nucleus of stria terminalis differently modulate the baroreflex function in unanesthetized rats.

The baroreflex is an important blood pressure regulating mechanism. The bed nucleus of stria terminalis (BNST) modulates the baroreflex function. However, the local BNST neurochemical mechanisms involved in control of baroreflex responses are not completely understood. Therefore, in this study, we investigated the involvement of corticotropin-releasing factor (CRF) receptors within the BNST in baroreflex control of heart rate in unanesthetized rats. For this, we evaluated effects of bilateral microinjection into the BNST of either the selective CRF1 receptor antagonist CP376395 (5 nmol/100 nL) or the selective CRF2 receptor antagonist antisauvagine-30 (5 nmol/100 nL) in bradycardiac response evoked by blood pressure increases caused by intravenous infusion of phenylephrine as well as tachycardiac response to blood pressure decrease caused by intravenous infusion of sodium nitroprusside. Bilateral microinjection of CP376395 into the BNST decreased the baroreflex bradycardiac response without affecting the reflex tachycardia. Conversely, BNST treatment with antisauvagine-30 decreased heart rate response during blood pressure drop without affecting the reflex bradycardia. Overall, these findings provide evidence of an involvement of CRF neurotransmission within the BNST in baroreflex activity. Nevertheless, data indicate that local CRF1 and CRF2 receptors differently modulate the baroreflex control of heart rate.

Both N-methyl-D-aspartate and non-N-methyl-D-aspartate glutamate receptors in the bed nucleus of the stria terminalis modulate the cardiovascular responses to acute restraint stress in rats.

The bed nucleus of the stria terminalis (BNST) is a forebrain structure that has been implicated on cardiovascular responses evoked by emotional stress. However, the local neurochemical mechanisms mediating the BNST control of stress responses are not fully described. In our study we investigated the involvement of glutamatergic neurotransmission within the BNST in cardiovascular changes evoked by acute restraint stress in rats. For this study, we investigated the effects of bilateral microinjections of selective antagonists of either N-methyl-D-aspartate (NMDA) or non-NMDA glutamate receptors into the BNST on the arterial pressure and heart rate increase and the decrease in tail skin temperature induced by acute restraint stress. Microinjection of the selective NMDA glutamate receptor antagonist LY235959 (1 nmol/100 nL) into the BNST decreased the tachycardiac response to restraint stress, without affecting the arterial pressure increase and the drop in skin temperature. Bilateral BNST treatment with the selective non-NMDA glutamate receptor NBQX (1 nmol/100 nL) decreased the heart rate increase and the fall in tail skin temperature, without affecting the blood pressure increase. These findings indicate a facilitatory influence of BNST glutamatergic neurotransmission via coactivation of local NMDA and non-NMDA receptors on the tachycardiac response to stress, whereas control of sympathetic-mediated cutaneous vasoconstriction is selectively mediated by local non-NMDA glutamate receptors.

Involvement of Type 1 Angiontensin II Receptor (AT1) in Cardiovascular Changes Induced by Chronic Emotional Stress: Comparison between Homotypic and Heterotypic Stressors.

Consistent evidence has shown an important role of emotional stress in pathogenesis of cardiovascular diseases. Additionally, studies in animal models have demonstrated that daily exposure to different stressor (heterotypic stressor) evokes more severe changes than those resulting from repeated exposure to the same aversive stimulus (homotypic stressor), possibly due to the habituation process upon repeated exposure to the same stressor. Despite these pieces of evidence, the mechanisms involved in the stress-evoked cardiovascular dysfunction are poorly understood. Therefore, the present study investigated the involvement of angiotensin II (Ang II) acting on the type 1 Ang II receptor (AT1) in the cardiovascular dysfunctions evoked by both homotypic and heterotypic chronic emotional stresses in rats. For this purpose, we compared the effect of the chronic treatment with the AT1 receptor antagonist losartan (30 mg/kg/day, p.o.) on the cardiovascular and autonomic changes evoked by the heterotypic stressor chronic variable stress (CVS) and the homotypic stressor repeated restraint stress (RRS). RRS increased the sympathetic tone to the heart and decreased the cardiac parasympathetic activity, whereas CVS decreased the cardiac parasympathetic activity. Additionally, both stressors impaired the baroreflex function. Alterations in the autonomic activity and the baroreflex impairment were inhibited by losartan treatment. Additionally, CVS reduced the body weight and increased the circulating corticosterone; however, these effects were not affected by losartan. In conclusion, these findings indicate the involvement of angiotensin II/AT1 receptors in the autonomic changes evoked by both homotypic and heterotypic chronic stressors. Moreover, the present results provide evidence that the increase in the circulating corticosterone and body weight reduction evoked by heterotypic stressors are independent of AT1 receptors.

Effects of nitric oxide synthesis inhibitor or fluoxetine treatment on depression-like state and cardiovascular changes induced by chronic variable stress in rats.

Comorbidity between mood disorders and cardiovascular disease has been described extensively. However, available antidepressants can have cardiovascular side effects. Treatment with selective inhibitors of neuronal nitric oxide synthase (nNOS) induces antidepressant effects, but whether the antidepressant-like effects of these drugs are followed by cardiovascular changes has not been previously investigated. Here, we tested in male rats exposed to chronic variable stress (CVS) the hypothesis that nNOS blockers are advantageous compared with conventional antidepressants in terms of cardiovascular side effects. We compared the effects of chronic treatment with the preferential nNOS inhibitor 7-nitroindazole (7-NI) with those evoked by the conventional antidepressant fluoxetine on alterations that are considered as markers of depression (immobility in the forced swimming test, FST, decreased body weight gain and increased plasma corticosterone concentration) and cardiovascular changes caused by CVS. Rats were exposed to a 14-day CVS protocol, while being concurrently treated daily with either 7-NI (30 mg/kg) or fluoxetine (10 mg/kg). Fluoxetine and 7-NI prevented the increase in immobility in the FST induced by CVS and reduced plasma corticosterone concentration in stressed rats. Both these treatments also prevented the CVS-evoked reduction of the depressor response to vasodilator agents and baroreflex changes. Fluoxetine and 7-NI-induced cardiovascular changes independent of stress exposure, including cardiac autonomic imbalance, increased intrinsic heart rate and vascular sympathetic modulation, a reduction of the pressor response to vasoconstrictor agents, and impairment of baroreflex activity. Altogether, these findings provide evidence that fluoxetine and 7-NI have similar effects on the depression-like state induced by CVS and on cardiovascular function.

CRF1 and CRF2 receptors in the bed nucleus of the stria terminalis modulate the cardiovascular responses to acute restraint stress in rats.

The corticotropin-releasing factor (CRF) is involved in behavioral and physiological responses to emotional stress through its action in several limbic structures, including the bed nucleus of the stria terminalis (BNST). Nevertheless, the role of CRF1 and CRF2 receptors in the BNST in cardiovascular adjustments during aversive threat is unknown. Therefore, in the present study we investigated the involvement of CRF receptors within the BNST in cardiovascular responses evoked by acute restraint stress in rats. For this, we evaluated the effects of bilateral treatment of the BNST with selective agonists and antagonists of either CRF1 or CRF2 receptors in the arterial pressure and heart rate increase and the decrease in tail skin temperature induced by restraint stress. Microinjection of the selective CRF1 receptor antagonist CP376395 into the BNST reduced the pressor and tachycardiac responses caused by restraint. Conversely, BNST treatment with the selective CRF1 receptor agonist CRF increased restraint-evoked arterial pressure and HR responses and reduced the fall in tail skin temperature response. All effects of CRF were inhibited by local BNST pretreatment with CP376395. The selective CRF2 receptor antagonist antisalvagine-30 reduced the arterial pressure increase and the fall in tail skin temperature. The selective CRF2 receptor agonist urocortin-3 increased restraint-evoked pressor and tachycardiac responses and reduced the drop in cutaneous temperature. All effects of urocortin-3 were abolished by local BNST pretreatment with antisalvagine-30. These findings indicate an involvement of both CRF1 and CRF2 receptors in the BNST in cardiovascular adjustments during emotional stress.

Aspectos do trauma hepatico: a proposito de 706 casos / Features of the hepatic injuries about 706 cases

A analise retrospectiva de 2.893 prontuarios de pacientes submetidos a laparotomia por trauma, de 1978 a 1987, no Hospital de Pronto Socorro (HPS), evidenciou 706 casos de traumatismos do figado onde foram mais acometidos os adultos jovens do sexo masculino; predominou o trauma aberto (76,21%) com armas brancas e armas de fogo como principais agentes; o trauma fechado foi produzido em sua maioria por acidentes de transito, acompanhado de lesoes mais graves, maior numero de lesoes associadas e maior reposicao volemica. A cirurgia mais empregada foi a hepatorrafia simples e as complicacoes pos-operatorias mais comuns foram hipovolemia, hemoperitonio, peritonite e hemorragia digestiva alta, estando a primeira mais intimamente relacionada com os traumas fechados