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Biomedical subjects

K Starke

Publications and source records attributed to K Starke.

At least 253 records · Page 14Linked to original sources
PubMed1977

Presynaptic receptor systems on the noradrenergic neurones of the rabbit pulmonary artery.

A search was performed for presynaptic, release-modulating receptor systems on the post-ganglionic sympathetic nerves of rabbit pulmonary artery. Strips of the artery were preincubated with (-)-3H-noradrenaline and then superfused and stimulated transmurally. 1. Tetrodotoxin, guanethidine, and omission of calcium all suppressed the stimulation-evoked overflow of tritium, thus confirming selective release from noradrenergic neurones. 49% of the stimulation-evoked overflow of total consisted of 3H-noradrenaline, 22% of 3H-3,4-dihydroxyphenyglycol (DOPEG), and 9% of 3H-normetanephrine. Cocaine virtually abolished the evoked overflow of 3H-DOPEG; further addition of corticosterone also abolished that of 3H-normetanephrine. In the presence of cocaine plus corticosterone, unmetabolized 3H-noradrenaline accounted for 86% of the stimulation-evoked overflow of total tritium. The overflow evoked per pulse was 2.2 X 10(-5) of the tritium content of the tissue (1 Hz); it increased 2-fold when the frequency was raised to 8 Hz. 2. Presynaptic alpha-adrenoceptors have previously been demonstrated in this tissue (Starke et al., 1975b). High concentrations of isoprenaline reduced the stimulation-evoked overflow of tritium, presumably by alpha-adrenergic inhibiton. No presynaptic effect of up to 10(-5) M normetanephrine and metanephrine was found. 3. Dopamine slightly diminished the stimulation-evoked overflow of tritium, but only at 100 times the inhibitory threshold concentration of noradrenaline (which is 10(-8) M; Starke et al., 1975b), probably through activation of presynaptic alpha-adrenoceptors. Apomorphine failed to reduce the evoked overflow whether the superfusion medium contained cocaine and corticosterone or not. 4. Isoprenaline (10(-9) -10(-6) M) did not change the evoked overflow whether the medium contained cocaine and corticosterone or not, and whether the frequency was 1 or 2 Hz. Propranolol also had no effect. 5. Angiotensin II increased the stimulation-evoked overflow both in the absence and in the presence of cocaine and corticosterone. Equieffective concentrations of angiotensin I were 10 times higher. Saralasin had no effect, whereas 1-Sar,8-Ile-angiotensin produced a small increase. Both of the latter peptides behaved as presynaptic antagonists of angiotensin II. A presynaptically supramaximal concentration of the alpha-adrenergic agonist oxymetazoline prevented the facilitatory action of yohimbine, but not that of angiotensin II. Separation of 3H-compounds showed that angiotensin II caused a proportionate increase in stimulation-evoked overflow of 3H-noradrenaline, 3H-DOPEG, and 3H-normetanephrine; this finding rules out any inhibition of noradrenaline uptake mechanisms. 6. 10(-4) -10(-3) M acetylcholine caused hexamethonium-sensitive acceleration of basal tritium outflow. Much lower concentrations (10(-7) M and higher) reduced the overflow evoked by electrical stimulation. The evoked overflow of 3H-noradrenaline, 3H-DOPEG, and 3H-normetanephrine was proportionately decreased...

Acetylcholine↗
PubMed1977

[Number of smokers in students (results of a panel-study)].

65% of female and 45% of male enrolers score as non-smokers. This number does not change much in time of study. After studentship this number does not increase also, but the number of cigarettes smoked by the smokers is increasing. As the results of the panel-study (2000 students) show are the habits of smoking/non-smoking very stable. Smokers and non-smokers differ in various traits of personality.

Adolescent↗