In slice preparations from kitten striate cortex, long-term potentiation (up to 15 h) of field potentials was demonstrated after conditioning stimulation of white matter. Current source-density analysis and measurement of response latencies of cortical units indicated that the potentiation represented enhancement of both geniculo-cortical transmission in layer IV and intracortical transmission in layer II--III.

Action Potentials↗

PubMed1981

[Luminance-duration relationship in the electroretinogram (author's transl)].

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Animals↗

PubMed1981

Inhibition of human platelet functions by verapamil.

The effects of verapamil, a coronary vasodilator, on platelet functions was studied. Platelet aggregation induced by ADP, epinephrine or collagen was inhibited by verapamil in vitro. Calcium ionophore A23187-induced platelet aggregation was also inhibited by verapamil in a concentration dependent manner. In washed platelets, verapamil caused a dose-dependent inhibition of serotonin release induced either by thrombin or A23187 in the absence of extracellular calcium. Addition of 1 mM CaCl2 with A23187 or thrombin partially overcame this inhibition. Addition of 1 mM CaCl2 in the absence of verapamil had no effect on thrombin- or A23187-induced secretion. When verapamil was administered to the healthy volunteers at the dosage commonly used, inhibition of platelet aggregation was observed 2 hrs after the drug ingestion. It is of great interest that verapamil potentiated the anti-aggregating activity of prostacyclin in vitro. Our results may suggest a potential role for verapamil in the treatment of thrombotic disorders.

Adenosine Diphosphate↗

PubMed1981

Changes of adenosinetriphosphatase (ATPase) activities in lymphocytes from patients with carcinomas of the gastrointestinal tract.

The activities of both total and Oligomycin-sensitive ATPase in lymphocytes from patients with gastrointestinal tract (GI) carcinomas in different Karnofsky performance status (KPS) were determined to investigate whether or not the changes of these enzyme activities were correlated to those of the immune responsiveness of the patients. In the patients whose KPS indicated more than 50%, the mean value of the total ATPase activity in lymphocytes tended to increase slightly as compared with that determined in the control subjects, but the mean value of the Oligomycin-sensitive ATPase activity in lymphocytes tended to decrease slightly as compared with that determined in the control subjects. In the patients whose KPS indicated less than 30%, the mean values of the activities of both total and Oligomycin-sensitive ATPase in lymphocytes tended to decrease remarkably as compared with those determined in the control subjects. The ATPase activities in lymphocytes were suggested to be useful measures to the immune responsiveness of the patients with GI carcinomas.

Adenosine Triphosphatases↗

PubMed1981