RESUMO
In experiments on conscious rats it was found that preliminary microinjection of 100 nl 100 microM glutamic acid to the rostral commissural part of the solitary tract nucleus or to the caudal ventrolateral medulla increased a rise in colonic temperature induced by systemically applied endotoxin (3 microg/kg Escherichia coli lipopolysaccharide, i.p.) as compared to animals with intrabulbar injection of vehicle (control group). Preliminary microinjection of glutamate to the caudal commissural part of the solitary tract nucleus levelled the endotoxin-induced temperature response. After glutamate treatment of the caudal ventrolateral medulla there was a significant decrease in the noradrenaline content and decrease in the adrenaline level in the caudal (not significant) and rostral ventrolateral medulla (significant), as well as a small rise in noradrenergic activity at the solitary tract nucleus as compared to control animals. The post-mortem measurement of the optical density of brainstem tissues revealed its significant attenuation at the solitary tract nucleus and caudal ventrolateral medulla after glutamate as compared with these structures after vehicle. The involvement of monoaminergic systems of both structures under study in the initiation and control of temperature responses during endotoxemia is suggested.
Assuntos
Temperatura Corporal , Endotoxemia/fisiopatologia , Lipopolissacarídeos/toxicidade , Bulbo/fisiologia , Núcleo Solitário/fisiologia , Animais , Colo , Epinefrina/metabolismo , Ácido Glutâmico/farmacologia , Injeções Intraperitoneais , Lipopolissacarídeos/administração & dosagem , Lipopolissacarídeos/antagonistas & inibidores , Bulbo/metabolismo , Norepinefrina/metabolismo , Ratos , Ratos Wistar , Núcleo Solitário/metabolismoRESUMO
Serotonin, histamine, tryptophan administered in low doses were shown to protect the rat gastric mucosa against indomethacin-induced hemorrhages. When administered in high doses, serotonin retained the protective properties, while histamine and histidine, on the contrary, increased the hemorrhagic lesion of the tissue. Tryptophan and histidine given in low doses promoted a decrease of the indomethacin elevated levels of serotonin and histamine in the gastric mucosa.