Consulta: subjectFacets:"Defense reaction"
Registros recuperados: 3
Data/hora: 09/06/2024 09:37:41

Activation of Prophenoloxidase and Removal of Bacillus subtilis from the Hemolymph of Acheta domesticus (L.) (Orthoptera: Gryllidae)
Provedor de dados: Neotropical Entomology
Autores: SILVA,CLEONOR C.A. DA.
Insect phenoloxidase is considered an important mediator in defense reaction against pathogens and parasites. It is present in the hemolymph of most insects as an inactive proenzyme, called prophenoloxidase. In Acheta domesticus (L.) the phenoloxidase activity was studied in the presence of Bacillus subtilis. The bacteria induced the activation of the prophenoloxidase and increased the level of phenoloxidase activity when injected into the hemocoel of A. domesticus nymphs. The level of increase was comparable to those observed in nymphs injected with laminarin, an activator of the proenzyme. Incubating B. subtilis in serum with phenoloxidase activated in vitro and then injecting into the insects accelerated the removal of the bacteria from the hemolymph in...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Hemolynph; Phenoloxidase; Hemocyte; Defense reaction.
Ano: 2002
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1519-566X2002000300024

Evidence for a role of nitric oxide in hindlimb vasodilation induced by hypothalamic stimulation in anesthetized rats
Provedor de dados: Anais da Academia Brasileira de Ciências
Autores: Ferreira-Neto,Marcos L.; Possas,Olga S.; Lopes,Oswaldo U.; Cravo,Sérgio L.
Electrical stimulation of the hypothalamus produces cardiovascular adjustments consisting of hypertension, tachycardia, visceral vasoconstriction and hindlimb vasodilation. Previous studies have demonstrated that hindlimb vasodilation is due a reduction of sympathetic vasoconstrictor tone and to activation of beta2-adrenergic receptors by catecholamine release. However, the existence of a yet unidentified vasodilator mechanism has also been proposed. Recent studies have suggested that nitric oxide (NO) may be involved. The aim of the present study was to investigate the role of NO in the hindquarter vasodilation in response to hypothalamic stimulation. In pentobarbital-anesthetized rats hypothalamic stimulation (100 Hz, 150µA, 6 s) produced hypertension,...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Hindlimb blood flow; Hypothalamus; Electrical stimulation; Defense reaction.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652005000200005

Anatomical connections of the periaqueductal gray: specific neural substrates for different kinds of fear
Provedor de dados: Brazilian Journal of Medical and Biological Research
Autores: Vianna,D.M.L.; Brandão,M.L.
The periaqueductal gray (PAG) has been traditionally considered to be an exit relay for defensive responses. Functional mapping of its subdivisions has advanced our knowledge of this structure, but synthesis remains difficult mainly because results from lesion and stimulation studies have not correlated perfectly. After using a strategy that combined both techniques and a reevaluation of the available literature on PAG function and connections, we propose here that freezing could be mediated by different PAG subdivisions depending on the presence of immediate danger or exposure to related signaling cues. These subdivisions are separate functional entities with distinct descending and ascending connections that are likely to play a role in different...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Periaqueductal gray; Defense reaction; Fear; Escape; Freezing; Periaqueductal gray columns.
Ano: 2003
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2003000500002