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K A Wilson

Publications and source records attributed to K A Wilson.

14 recordsLinked to original sources
PubMed1990

Alpha 2-adrenoceptor antisecretory responses in the rat jejunum.

1. Addition of noradrenaline (5 microM), UK-14,304 (0.1 microM) or phenylephrine (100 microM) to the serosal surface of sheets of rat jejunum mounted in Ussing type chambers decreased resting transepithelial short circuit current (SSC). These responses were inhibited by the selective alpha 2-adrenoceptor antagonist idazoxan (0.5-5.0 microM) but were not significantly affected by the alpha 1-adrenoceptor antagonist corynanthine (100 microM). 2. All three agonists caused a dose-related reduction of SSC which had been elevated by prior addition of theophylline (4 mM). UK-14,304 was 8.1 times more potent than noradrenaline and 76.2 times more potent than phenylephrine. Idazoxan (10 nM-1 microM) caused rightward, parallel displacements of the concentration-response curves for noradrenaline and UK-14,304; PA2 values were 7.87 and 8.02 respectively. Dose-response curves to noradrenaline were unaffected by prazosin (1 microM). 3. The reduction by noradrenaline (10 microM) of SCC which had been elevated by theophylline (4 mM) was not significantly affected by tetrodotoxin (5 microM), suggesting that noradrenaline reduces SCC in rat jejunum via a direct mucosal mechanism. 4. The resting SCC was markedly reduced in chloride-free PSS and under these conditions, noradrenaline did not elicit any further fall in SCC. In bicarbonate-free physiological salt solution (PSS) the resting SCC and the noradrenaline-induced fall in SCC were not significantly different from those in normal PSS. It is concluded that the decrease in SCC observed with noradrenaline, UK-14,304 and phenylephrine is mediated via stimulation of postjunctional alpha 2-adrenoceptors.

Animals↗
PubMed1979

The role of calcium and cyclic AMP in the contractile action of angiotensin II upon rat descending colon.

The effect of procedures which affect calcium availability and tissue levels of cyclic AMP were investigated upon the contractions of rat colon to angiotensin II, PGE2 and KCl. Calcium free Tyrode containing EDTA (25 microM) reduced the response to angiotensin more than to PGE2 and KCl. An increase in calcium concentration to 3.6 mM potentiated responses to angiotensin and KCl. A further increase to either 7.2 mM or 10.8 mM still potentiated responses to angiotensin but those to KCl wre reduced. SKF 525A (2.6 x 10(-5) M) and verapamil (3.5 x 10(-6) M) inhibited the responses to KCl but the responses to PGE2 and angiotensin were less affected. Isoprenaline, Theophylline and dibutyryl cyclic AMP preferentially reduced the responses to angiotensin and PGE2. It is suggested that part of the response to angiotensin involves an influx of calcium, independent of depolarisation.

Angiotensin II↗
PubMed1979

Prostaglandins and the contractile action of bradykinin on the longitudinal muscle of rat isolated ileum.

1. The effect of the prostaglandin synthesis inhibitors aspirin and indomethacin (Ind) was investigated upon contractions of the perfused isolated terminal ileum of the rat to bradykinin (Bk) or potassium chloride (KCl). The release of a prostaglandin-like substance (PGLS) from the ileum was simultaneously assayed on the rat fundus strip (RFS). 2. Aspirin (610 micro M) or Ind (28 micro M) reduced contractions of the ileum to Bk perfused over the mucosal surface but not to Bk perfused over the serosal surface. 3. After perfusion of either ileal surface the effluent potentiated the contractions of the RFS to Bk. No potentiation was observed in the presence of either Ind or aspirin. 4. Contractions of the RFS to Bk were potentiated by prostaglandin E2 (PGE2) (0.7 X 10(-12) M and 1.4 X 10(-12) M) but not by either a higher (2.8 x 10(-12) M) or a lower (0.35 X 10(-12) M) concentration of PGE2. No potentiation was observed with prostaglandin F2 alpha (PGF2 alpha) at the concentrations studied. 5. Only the contractile action of Bk acting on the mucosal surface of the rat isolated perfused ileum seems to involve prostaglandin synthesis.

Animals↗
PubMed1978

Physiological aspects of menopausal hot flush.

Eighteen hot flushes experimenced by eight menopausal women were studied and compared with the effects of warming in six premenopausal women. The hot flushes were associated with an acute rise in skin temperature, peripheral vasodilatation, a transient increase in heart rate, fluctuations in the electrocardiographic (ECG) baseline, and a pronounced decrease in skin resistence. Although premenopausal women had greater maximum increases in skin temperature and peripheral vasodilatation, they showed a much smaller decrease in skin resistance and no changes in heart rate or ECG baseline. These findings suggest that the onset of the hot flush is associated with a sudden and transient increase in sympathetic drive. Further investigations may lead to the development of a more specific alternative to oestrogen for relieving menopausal hot flushes.

Blood Pressure↗
PubMed1975

The partial amino acid sequence of trypsin inhibitor II from garden bean, Phaseolus vulgaris, with location of the trypsin and elastase-reactive sites.

The amino acid sequences of garden bean (Phaseolus vulgaris) trypsin inhibitor II and a related molecular species II' have been examined. The entire sequence of II' has been determined with the exception of five internal residues. The garden bean inhibitors are highly homologous to the Bowman-Birk soybean inhibitor and lima bean trypsin inhibitor IV. The trypsin-reactive site has been located in the second half of the molecule, while the first reactive site has been found to be directed against elastase. Garden bean inhibitor II (and II') is thus a double-headed inhibitor, simultaneously inhibiting 1 molecule of trypsin and 1 of elastase.

Amino Acid Sequence↗
PubMed1975

A further investigation into the energy dependence of angiotensin II-induced contractions of isolated smooth muscle preparations.

1 The energy dependence of angiotensin and acetylcholine-induced contractions of rat descending colon and uterus was investigated. 2 Differences were observed in the effect of anaerobic substrate depletion upon responses of colon and oestrous and dioestrous uterus. These were attributed to differences in the energy metabolism of the tissues and were correlated with differences in tissue levels of glycogen. 3 The preferential reduction of angiotensin responses of dioestrous uterus and descending colon when exposed to 2,4-dinitrophenol, was evidence for an energy dependent stage in the angiotensin response distinct from the contraction process itself. 4 The absence of a preferential reduction of the angiotensin response of oestrous uterus when exposed to 2,4-dinitrophenol appeared to be related to the ability of this tissue to generate ATP by anaerobic glycolysis. 5 It was concluded that the energy for the angiotensin response may be derived either anaerobically or aerobically, depending upon the tissue.

Angiotensin II↗