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Biomedical subjects

J Nordmann

Publications and source records attributed to J Nordmann.

At least 109 records · Page 6Linked to original sources
PubMedDate not supplied

Brain membrane disordering related to acute ethanol administration in naive and short-term ethanol-intoxicated rats.

Crude synaptic membrane fluidity (checked by fluorescence polarization) together with (Na+ + K+) ATPase activity were examined 18 hours after a single oral ethanol administration (5 g/kg bwt.) to naive rats and to rats previously intubated with ethanol repeatedly during 4 days. The sensibility of both parameters to different concentrations of ethanol added in vitro (0.175 M-1.400 M) was also determined. Although no changes in the basal intrinsic fluidity were found, (Na+ + K+)ATPase activity increased slightly in both conditions. The fluidizing as well as the ATPase inhibiting effects following the addition of ethanol in vitro were markedly increased 18 hours after ethanol administration to naive rats. This hypersensitization was no longer apparent in rats pretreated with ethanol during 4 days. The acute ethanol-induced hypersensitization found in naive rats appears not to be related to an unspecific stress or to changes in body temperature. The disappearance of this hypersensitization in short-term alcohol-intoxicated animals may represent the first stage of tolerance acquisition.

Alcoholic Intoxication↗
PubMedDate not supplied

Brain membrane sensitivity to ethanol during development of functional tolerance to ethanol in rats.

Adult male rats were rendered progressively tolerant to ethanol by daily intragastric administration of doses of 3-6 g/kg body weight. Functional tolerance assessed by the hypothermic effect after injection of a challenge dose of ethanol developed slowly and was demonstrable after 2 weeks of treatment. Intrinsic crude synaptosomal membrane fluidity, as assessed by fluorescence polarization of DPH, as well as (Na+ + K+)ATPase activity, did not change significantly during the whole treatment. However, the extra addition of ethanol (0.175-0.700 M) in vitro to the membranes of rats, having received ethanol over a period of at least 2 weeks, fluidized less and inhibited the (Na+ + K+)ATPase activity less than in starch-fed controls. The time-course for the appearance of this membrane hyposensitivity was found to be the same as the time course for the development of functional tolerance to ethanol. The correlation between the degree of functional tolerance and the (Na+ + K+)ATPase sensitivity to ethanol appeared very significant, highlighting the sensitivity of membrane-bound enzymes to detecting adaptive changes in complex biological membranes tolerance.

Animals↗
PubMedDate not supplied

[Na-K-ATPase activity in the normal aging crystalline lens and in senile cataract].

Activity of Na-K-ATPase decreases in normal bovine and human lens with age. In senile cataract this tendency continues to some extent. In most lenses, clear or opaque, the presence of an inhibitor to Na-K-ATPase can be demonstrated. Its activity which is not influenced by a dialysis, seems to vary greatly. So it is impossible for the moment being to draw conclusions on this special point, except perhaps a certain increase of the inhibition during aging.

Adenosine Triphosphatases↗