Search PubMed⌕ Search

Biomedical subjects

W A Wilson

Publications and source records attributed to W A Wilson.

At least 163 records · Page 9Linked to original sources
PubMed1977

Penicillin effects on iontophoretic responses in Aplysia californica.

The effect of penicillin on neurons of Aplysia californica was studied using drug concentrations which would be convulsant in mammalian nervous systems. Iontophoretic responses were elicited by the application of acetylcholine, dopamine, gamma-aminobutyric acid and serotonin. Low concentrations of penicillin (2 mM) consistently and reversibly reduced the chloride-dependent hyperpolarizing responses by approximately 70%, regardless of the transmitter required to evoke them. The short depolarizing responses which are sodium sensitive are slightly reduced by a much higher (10 mM) concentration. The extent of the reduction of the excitatory response varied with the transmitter. The slow sodium-dependent depolarizations and the slow potassium-dependent hyperpolarizations were unaffected by the concentrations of penicillin used. The possibility that the convulsant effect of penicillin is due to interference with membrane conductance to chloride is discussed.

Acetylcholine↗
PubMed1977

Synaptic mechanism of pentylenetetrazole: selectivity for chloride conductance.

In the neurons of Aplysia californica pentylenetetrazole (2 millimolar) greatly reduced chloride-dependent responses to the iontophoresis of putative transmitters. At the same concentration, pentylenetetrazole caused less attenuation of the other iontophoretic responses and had minimal membrane effects. Several convulsants have been observed to have a similar selectivity for the chloride conductance. A common mechanism of convulsant action--reduction of transmitter-induced chloride conductances--is hypothesized.

Acetylcholine↗
PubMed1977

Tris buffer attenuates acetylcholine responses in Aplysia neurons.

The commonly used buffering agent tris(hydroxymethyl)methylamine (tris) antagonizes the action of iontophoretically applied acetylcholine on neurons of Aplysia californica. Concentrations of 5 to 10 millimolar tris markedly reduced both excitatory and inhibitory responses.

Acetylcholine↗
PubMed1977

Development of the single microelectrode current and voltage clamp for central nervous system neurons.

The development of a single microelectrode clamping circuit for central nervous system preparations is presented. The efficacy of the circuit in both current and voltage clamp modes is demonstrated by investigating the membrane properties of cat spinal motoneurons. Results are compared with those obtained using conventional techniques and reveal that this technique can be more readily applied to central nervous system neurons. The constraints invovled in employing this system to study time-varying events are also discussed.

Animals↗
PubMed1977

Effects of prestriate, inferotemporal, and superior temporal sulcus lesions on attention and gaze shifts in rhesus monkeys.

The role of extrastriate cortical areas in selective attention was studied in 12 rhesus monkeys. Animals learned a series of color-form pattern discrimination problems, with either color or form cues relevant. After each problem was mastered, correct behavior required a shift in attention, i.e., that responses be made to be previously irrelevant dimension. On some problems shifting attention required that the animal maintain the same fixation; on other problems the color and form cues were separated in space, and the attention shift presumably required a shift in gaze. Matched groups of animals with inferotemporal, prestriate, or superior temporal sulcus lesions, and normal controls, differed significantly in their ability to shift attention. Analyses of inferred stages in attention shift showed that different processes were disturbed in the three lesion groups. Results are discussed in terms of cortical substrates for "looking" and "seeing".

Animals↗
PubMed1977

Medical truants.

Explore the source record for details and available documents.

Famous Persons↗
PubMed1977

Lest we forget.

Explore the source record for details and available documents.

Dentistry↗
PubMed1976

Deficiency of factor B of the complement system in sickle cell anaemia.

Factors B and D as well as the total activity of the alternative pathway of complement activation were measured using a functional assay in sera from 29 patients with sickle cell anaemia and 18 normal controls. Total alternative pathway activity was reduced in the patients compared with controls. In patients with abnormally low total alternative pathway activity factor D levels were normal, whereas factor B levels were significantly depressed to a mean level of about half of normal. Regression analysis in patients also showed a significant relation between total alternative pathway activity and factor B levels. A deficiency of factor B is the likely cause of the defect in the complement system in patients with sickle cell anaemia. Such a defect may contribute to the excessive proneness of such patients to severe infection.

Adult↗