Effect of constant light and immobilization stress on rat submandibular saliva secretory response induced by cholinergic and peptidergic agonists

The aim of this work was to analyse the parasympathetic control of submandibular saliva secretory response to cholinergic and peptidergic agonists in rats chronically exposed to constant light or repeated immobilization. Thirty two adult male Wistar rats were used: LL (8 rats exposed to constant light for 20 days), IMO (8 rats submitted to 14:10 h light: dark cycle and immobilized 2 hours daily for 7 days), and control (16 rats not exposed to stress and submitted to 14:10 hours light:dark cycle). Saliva was collected under anesthesia from the salivary ducts of submandibular glands under increasing doses of methacholine and substance P. Secretory responses (µg/saliva/mg dry weight gland) to methacholine were significantly higher in LL and IMO groups compared to control for the following doses (µg/kg body weight): 3 (153±9 versus 46±3, p<0.001 and 76±3 versus 40±3, p<0.001), 10 (379±23 versus 277±8, p<0.001 and 275±19 versus 250±10, p<0.01) and 30 (729±25 versus 695±19, p<0.05 and 1008±39 versus 640±20, p<0.001). Also, responses to substance P were significantly increased in LL and IMO groups compared to control for the following doses: 0.2 (80±3 versus 30±3, p<0.01 and 94±16 versus 31±3, p<0.001), 0.5 (328±20 versus 231±16, p<0.01 and 531±31 versus 219±25,p<0.001), 1 (681±35 versus 547±30, p<0.01 and 1031±63 versus 563±53, p<0.001), and 5 (2222±88 versus 1868±59, p<0.01 and 3230±145 versus 1921±218, p<0.001). In conclusion, supersensitivity of secretory response to both agonists suggests that chronic exposure of rats to stressors capable of activating the sympathetic adrenal system promotes inhibition of the parasympathetic control of salivary secretion.

Diagnosis and treatment of anaphylaxis: there is an urgent needs to implement the use of guidelines / Diagnóstico e tratamento da anafilaxia: há necessidade urgente de implementar o uso das diretrizes

ABSTRACT Anaphylaxis is a severe, life-threatening generalized or systemic hypersensitivity reaction that requires rapid and adequate care. This study aimed to obtain an integrated view of the level of physicians' knowledge related with treatment of anaphylaxis in studies published within the last 5 years. Sixteen studies were found and four points were identified as of the great interest to the authors: (1) emergency pharmacological treatment, (2) epinephrine auto-injectors prescription, (3) knowledge of the main signs of anaphylaxis, and (4) admission of the patient to verify biphasic reactions. Concern about the use of intramuscular adrenaline as the first choice in relation with anaphylaxis was evident in most studies, rather than its use in the comparison dial, and especially low in a study that included data from Brazil, in which the frequency of its use was 23.8%. An adrenaline autoinjector is highly recommended among specialists for patients at risk of anaphylaxis, however, its use is still infrequent among non-specialists and in countries that this agent is not available. Intervention studies have shown improved medical knowledge of anaphylaxis following disclosure of the information contained in the international guidelines. The analysis of these studies reinforces the need to disseminate international guidelines for diagnosis and treatment of anaphylaxis, as well as providing an adrenaline autoinjector, to improve management and to prevent a fatal outcome.

RESUMO Anafilaxia é uma reação de hipersensibilidade generalizada ou sistêmica grave, com risco de morte, que exige atendimento rápido e correto. Este estudo teve como objetivo obter uma visão integrada do nível de conhecimento dos médicos no atendimento da anafilaxia à luz dos estudos publicados internacionalmente nos últimos 5 anos. Foram encontrados 16 estudos, com quatro pontos identificados como de maior interesse dos autores: (1) tratamento farmacológico de emergência, (2) prescrição de autoinjetores de adrenalina, (3) conhecimento dos principais indícios da anafilaxia e (4) observação do paciente para verificar reações bifásicas. A preocupação com o uso da adrenalina intramuscular como primeira escolha frente à anafilaxia foi evidente na maioria dos estudos, mas o conhecimento sobre seu uso se mostrou desigual e especialmente baixo em estudo que incluiu dados do Brasil, onde a frequência de seu uso foi de 23,8%. A adrenalina autoinjetável é altamente recomendada entre especialistas para pacientes em risco de anafilaxia, mas seu uso ainda é pouco frequente entre não especialistas e em países que não dispõem dela em seus mercados internos. Estudos de intervenção comprovaram a melhora no entendimento dos médicos sobre anafilaxia após a divulgação das informações contidas nas diretrizes internacionais. A análise dos estudos reforça a necessidade de disseminar as diretrizes internacionais no manejo da anafilaxia, bem como de disponibilizar a adrenalina autoinjetável, a fim de melhorar o atendimento e evitar um desfecho fatal.

Anaphylaxis.

Anaphylaxis must always be considered a medical emergency. While classic anaphylaxis needs specific antigen to trigger IgE antibody-mediated reaction, idiopathic anaphylaxis spontaneously occurs with no external allergen. Anaphylactoid are not mediated by antigen-antibody but result from substances acting directly on mast cells and basophils. Incidence of anaphylaxis is 21 per 100,000 person-years with fatality in about 0.65% of cases. Food is the most frequent cause of anaphylaxis in children while insect sting is the most common cause in adults. Epinephrine is the first pharmacological treatment. Secondary measures include circulatory support, H1 and H2 antagonists, bronchodilators if necessary and probably corticosteroids. Since life-threatening manifestations may recur during the recurrent phase, it may be necessary to observe the patients for up to 48 hours after apparent recovery from an anaphylactic episode.

Efeitos hemogasométricos da xilazina e da romifidina em cabras tratadas por ioimbina / Haemogasometric effects of xylazine and romifidine in goats treated with yohimbine

Estudaram-se as alterações produzidas por doses equipotentes de xilazina e romifidina e os efeitos da administração subseqüente de ioimbina em oito cabras mestiças. Respeitou-se um intervalo de sete dias entre os seguintes tratamentos: A- 250µg/kg/IM de xilazina e 0,1ml/kg/IV de solução fisiológica, B- 250µg/kg/IM de xilazina e 250µg/kg/IV de ioimbina, C- 25µg/kg/IM de romifidina e 0,1ml/kg/IV de solução fisiológica, D- 25µg/kg/IM de romifidina e 250µg/kg/IV de ioimbina. Foram mensurados a freqüência respiratória, o pH, as pressões parciais de oxigênio e dióxido de carbono, a concentração de íon bicarbonato, o excesso de bases e a saturação de oxigênio no sangue arterial. Utilizou-se um delineamento experimental crossover, e as médias foram comparadas pelo teste Duncan (Pmenor ou igual a 0,05). Xilazina e romifidina reduziram a pressão arterial de oxigênio e aumentaram a pressão arterial de dióxido de carbono. A ioimbina reverteu os efeitos da xilazina e da romifidina sobre as pressões parciais de oxigênio e dióxido de carbono no sangue arterial.

Safety of subcutaneous adrenaline as prophylaxis against acute adverse reactions to anti-venom serum in snakebite.

OBJECTIVES: To study the safety of low dose subcutaneous adrenaline given as prophylaxis against acute adverse reactions to anti-venom serum (AVS) in patients bitten by snakes. METHODS: Patients admitted with snakebite envenoming who satisfied inclusion criteria were given 0.25 ml of 1:1000 adrenaline subcutaneously immediately before administration of AVS. They were observed for adverse effects, and pulse and blood pressure (BP) were monitored. RESULTS: 51 patients [35 males, mean age 34.8 years (SD 14)] were included in the study. Adverse reactions to AVS occurred in 15 (29.4%) patients. There was one death from suspected cerebral haemorrhage, and 3 (5.9%) patients developed small haematomas at the subcutaneous injection site. There were no significant changes in mean pulse or BP following administration of subcutaneous adrenaline. CONCLUSIONS: Low dose subcutaneous adrenaline did not cause significant changes in pulse rate or BP. Although the death was unlikely to be directly related to subcutaneous adrenaline, we suggest further studies on the safety of this prophylactic treatment before its routine use.

Modulation of feeding and drinking behaviour by catecholamines injected into nucleus accumbens in rats.

Nucleus accumbens is proposed as one of the centers in the neural circuitry involved in the regulation of feeding and drinking behaviour in rats. Injection of dopamine and angiotensin-II into this nucleus has been documented to affect water and food intake in rats. Reports on the effect of intracerebral injection of catecholamines on feeding and drinking behaviour in animal models are conflicting. Therefore, in the present study the effect of adrenaline and noradrenaline injected into nucleus accumbens on food and water intake in rats was assessed. 24 h basal food and water intakes were recorded in Wistar rats and were found to be 12.3 +/- 0.46 g and 21.7 +/- 1.03 ml respectively. Stainless steel cannulae were implanted stereotaxically into the nucleus accumbens. Four different doses (0.1 microgram, 0.5 microgram, 1 microgram, and 2 micrograms) of adrenaline and noradrenaline were injected into the nucleus accumbens through the implanted cannulae in different group of animals and their 24 h food and water intakes were recorded following these injections. No change in food and water intake was observed following the administration of different doses of adrenaline. A significant increase in 24 h water intake reaching a maximum of 28.88 +/- 1.45 ml at 1 microgram dose, without change in food intake was observed following administration of different doses of noradrenaline. The noradrenaline-facilitated water intake was blocked when noradrenaline was injected following injection of phentolamine, an alpha-receptor blocker. The bilateral lesions of nucleus accumbens resulted in a significant and sustained inhibition of water intake (16.61 +/- 0.67 ml) without change in food intake. These observations suggest that noradrenaline facilitates water intake without affecting food intake when injected into the nucleus accumbens in rats and the dipsogenic effect of noradrenaline is mediated by alpha-receptors. Adrenaline does not affect these ingestive behaviours when injected into the nucleus accumbens in rats.