Amygdalar neuronal activity mediates the cardiovascular responses evoked from the dorsolateral periaqueductal gray in conscious rats.

There is ample evidence that both lateral/dorsolateral periaqueductal gray (l/dlPAG) and basolateral amygdala (BLA) are essential for the regulation of the autonomic responses evoked during innate reactions to threatening stimuli. However, it is not well established to what extent the BLA regulates the upstream functional connection from the l/dlPAG. Here we evaluated the role of the BLA and its glutamatergic receptors in the cardiovascular responses induced by l/dlPAG stimulation in rats. We examined the influence of acute inhibition of the BLA, unilaterally, by injecting muscimol on the cardiovascular responses evoked by the injection of N-methyl D-aspartate (NMDA) into the l/dlPAG. We also evaluated the role of BLA ionotropic glutamate receptors in these responses by injecting antagonists of NMDA and AMPA/kainate receptor subtypes into the BLA. Our results show that the microinjection of NMDA in the BLA increased the mean arterial pressure (MAP) and heart rate (HR). Injection of NMDA into the l/dlPAG caused similar increases in these variables, which was prevented by the prior injection of muscimol, a GABAA agonist, into the BLA. Moreover, injection of glutamatergic antagonists (2-amino-5-phosphonopentanoate (AP5) and 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX)) into the BLA reduced the increase in MAP and HR induced by l/dlPAG activation. Finally, the inhibition of the central amygdala neurons failed to reduce the cardiovascular changes induced by l/dlPAG activation. These results indicate that physiological responses elicited by l/dlPAG activation require the neuronal activity in the BLA. This ascending excitatory pathway from the l/dlPAG to the BLA might ensure the expression of the autonomic component of the defense reaction.

Blunted GABA-mediated inhibition within the dorsomedial hypothalamus potentiates the cardiovascular response to emotional stress in rats fed a high-fat diet.

Rats fed a high-fat diet (HFD) present an exaggerated endocrine response to stress conditions, which, like obesity, show a high correlation with cardiovascular diseases. Meanwhile the GABAergic neurotransmission within the dorsomedial hypothalamus (DMH) is involved in the regulation of the physiological responses during emotional stress. Here we evaluated the influence of obesity, induced by a HFD, on the cardiovascular responses induced by air jet stress in rats, and the role of the GABAergic tonus within the DMH in these changes. Our results showed that consumption of a HFD (45% w/w fat) for 9 weeks induced obesity and increases in baseline mean arterial pressure (MAP) and heart rate (HR). Moreover, obesity potentiated stress responsiveness, evidenced by the greater changes in MAP and HR induced by stress in obese rats. The injection of muscimol into the DMH reduced the maximal increases in HR and MAP induced by stress in both groups; however, the reduction in the maximal increases in MAP in the HFD group was less pronounced. Moreover, the injection of muscimol into the DMH of obese rats was less effective in reducing the stress-induced tachycardia, since the HR attained the same levels at the end of the stress paradigm as after the vehicle injection. Injection of bicuculline into DMH induced increases in MAP and HR in both groups. Nevertheless, obesity shortened the tachycardic response to bicuculline injection. These data show that obesity potentiates the cardiovascular response to stress in rats due to an inefficient GABAA-mediated inhibition within the DMH.

Membrane protein patterns of three Azospirillum species and Herbaspirillum seropedicae.

Membrane protein patterns in SDS-PAGE clearly characterized Azospirillum amazonense, A. brasilense, A. lipoferum, and Herbaspirillum seropedicae. Each species showed also a typical major band with approximate molecular weights (AMWs) of 44, 39.5, 35.5, and 37.5 Kdaltons for the four species respectively. Characteristic lighter bands with AMWs of 63.5 and 19 Kdaltons were shown by A. amazonense. Similar bands of 54, 24 and 24.5 Kdaltons were typical of A. brazilense, A. lipoferum and H. seropedicae, respectively. The three Azospirillum species showed four identical proteins in common, out of the six main proteins presented in SDS-PAGE; H. seropedicae had only two major proteins with one of them common to all three Azospirillum species. The data strongly favors the maintenance of Azospirillum and Herbaspirillum as valid generic taxa as well as supports the validity of the three Azospirillum species.

Volvo do intestino delgado sem malrotacao intestinal. Relato de cinco casos. / Volvulus of the small intestine without intestinal malrotation. Report of 5 cases

O autor apresenta cinco casos de volvo do intestino delgado no periodo neonatal, sem malformacao intestinal. Em tres criancas este ocorreu no periodo fetal com consequentes atresias de jejuno em dois casos e ileo em um caso, e tiveram como fator determinante defeito de fixacao do mesenterio. Em uma outra crianca o volvo de jejuno ocorreu com seis dias de idade devido a bridas congenitas no mesenterio. Em um recem-nascido de dois dias o volvo foi causado por uma duplicacao cistica do ileoterminal. Tres criancas sobreviveram (60%) e duas morreram (40%), uma no segundo dia de pos-operatorio, com complicacoes pulmonares e a outra no quarto dia, de sepse durante nutricao prolongada

Apendice lombar. / Lumbar appendix

Os autores apresentam dois casos de apendice lombar, anomalia de fechamento do neuroporo posterior, em duas criancas; uma de oito anos de idade e a outra um recemnascido. Chamam a atencao para a diferenca entre a origem embriologica dos apendices lombar e caudal, e advertem para os cuidados que deverao ser tomados durante a cirurgia. Discutem a dificuldade de se estudar melhor a origem embriologica destas malformacoes em virtude da grande raridade destes casos

Diverticulo de Meckel obstruido por cicatrizacao ulcerosa. / Meckel's diverticulum blocked by ulcerous cicatrization

O autor relata o caso de uma crinca de sete meses de idade, portadora de diverticulo de Meckel com brida onfalomesenterica que apresentou 3 importantes complicacoes enterorragia, inflamacao e obstrucao intestinal. A hemorragia, devido a ulceracao do diverticulo. A inflamacao foi provocada mais tarde pelo processo de fibrose cicatricial da ulcera que obstruiu a luz do diverticulo e aprisionou restos alimentares em sua extremidade distal. A obstrucao intestinal foi causada por volvo em torno do diverticulo, e motivou a cirurgia