RESUMO
When mouse diaphragms are incubated in vitro with [14C] inositol, radioactivity is observed at post synaptic areas in phosphatidyl-inositols and in inositol-phosphates. Synaptic desensitization suppresses the labelled inositol-phosphates. Lindane restores the labelling effect without suppressing the desensitized state.
Assuntos
Inositol/metabolismo , Contração Muscular , Músculos/fisiologia , Sinapses/fisiologia , Animais , Autorradiografia , Radioisótopos de Carbono , Masculino , Camundongos , Músculos/inervação , Músculos/metabolismoRESUMO
Residual radioactivity in Rat brain structures is studied after single dose 14C Lindane administration. Short time after injection, at the onset of convulsions, white matter and myelinated structures show important retention, nucleated cells do not. This heterogeneous distribution agrees with the lipophilic behaviour of the pesticide.
Assuntos
Encéfalo/metabolismo , Hexaclorocicloexano/metabolismo , Animais , Autorradiografia , Hexaclorocicloexano/administração & dosagem , Hexaclorocicloexano/toxicidade , Masculino , Ratos , Ratos Endogâmicos , Convulsões/metabolismo , Fatores de TempoRESUMO
Alizarin red S (ARS) is used for histological characterization of calcium. In order to improve the conditions of the use of the dye on biological materials, the chemical reaction between ARS and Ca2+ is studied in vitro. In aqueous solution ARS and Ca2+ ions precipitate to form brick-red deposits. For precipitation to occur a neutral pH (4 less than pH less than 8) is required; the stoichiometric ratio is 1:1. ARS reacts with calcium via its sulfonate and hydroxyl groups. The apparent solubility product is around 10(-7) Na+ and K+ ions do not interfere with equilibrium of the precipitation reaction but Mg2+ and soluble proteins such as bovine serum albumin react with ARS and form soluble complexes which can lead to a decrease in the ARS quantity available to react with the calcium ions.
Assuntos
Antraquinonas , Cálcio/análise , Animais , Cálcio/farmacologia , Cromatografia em Gel , Eletroforese , Histocitoquímica , Técnicas In Vitro , Magnésio/farmacologia , Camundongos , Potássio/farmacologia , Proteínas/farmacologia , Sódio/farmacologia , SoluçõesRESUMO
The peripheral neurotoxicity of lindane was studied in vitro on mouse phrenic-diaphragm preparation. The experiments were performed on normal and denervated preparations. Twitches evoked by direct or indirect electrical stimulations and contractions evoked by external application of cholinergic agonists were compared in the presence or absence of lindane in the bath medium. Histochemical localizations of calcium were made on fibers after chemical stimulations. The results indicated that, at the normal endplate or at extrajunctionnal sites after denervation, there was a change in the intracellular Ca2+ distribution in response to external application of concentrated cholinergic agonists. This modification caused a transient contracture and could be visualized either by 45Ca autoradiography or by Alizarin Red S intracellular precipitations. Lindane inhibited the ACh-dependent contracture (I50 less than 10(-5) M) and suppressed the histochemical localizations of calcium. These lindane effects were observed on both normal and denervated muscles. It was concluded that lindane inhibited the Ca2+ influx presented by the desensitized ACh-sensitive areas of the muscle.