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Biomedical subjects

L Edvinsson

Publications and source records attributed to L Edvinsson.

At least 487 records · Page 27Linked to original sources
PubMed1975

Measurement of endometrial blood flow in guinea-pig uterus by clearance of intraluminally applied 133xenon: effects of oophorectomy, estrogen treatment and pregnancy.

Endometrial blood flow (EBF) was studied atraumatically in guinea-pigs by the 133xenon clearance technique. With the aid of an otoscope, a xdnon-saline solution was deposited via the vagina through a cannula into the uterine lumen. Radioactivity curves were obtained by a small external scintillation detector. Oophorectomy lowered total flow wheras this was markedly increased (also per unit weight) by estrogen treatment, alone or in combination with oophorectomy. During early pregnancy there was a tendency to increase in the flow, while the values (for the parietal decidua) were markedly reduced at later stages of pregnancy. In the fetus-placenta unit (133xenon solution injected intra-amniotically) the flow was three times higher than in the parietal decidua at this advanced stage of pregnancy.

Animals↗
PubMed1975

Neurogenic influence on local cerebral blood flow. Effect of catecholamines or sympathetic stimulation as correlated with the sympathetic innervation.

Local cerebral flow was measured continuously in conscious rabbits (thermoclearance technique), and PaO2 and PaCO2 were recorded by mass spectrometry. Though inhalation of CO2 increased flow in caudate nucleus and lateral geniculate body, catecholamines only had effect on caudate nucleus where isoproterenol enhanced and epinephrine and norepinephrine reduced flow. Reduction by electrical stimulation of the neck sympathetic trunk was particularly evident in the caudate. Blood flow increased markedly in both regions after preganglionic conduction blockade. The effects were correlated with a significantly lower degree of sympathetic arteriolar innervation (fluorescence histochemistry) in the lateral geniculate body compared with the caudate nucleus.

Animals↗
PubMed1975

A pharmacologic comparison of histamine receptors in isolated extracranial and intracranial arteries in vitro.

Isolated segments of cat extracranial and intracranial arteries were tested simultaneously for circular motor activity in an aerated Krebs-Ringer organ bath at constant temperature and pH. Histamine produced a strong contraction (about 850 dyn) in the extracranial arteries but a considerably weaker contraction, with a high half maximum response, in the intracranial arteries. The mode of inhibition of the latter response by antihistaminic compounds (chlorpheniramine and mepyramine) showed the response to be nonspecific; the contraction in the extracranial arteries was inhibited in a competitive manner, demonstrating the presence of histamine H1 receptors. The dilatory response was studied after the vessels had been given a tonic contraction with serotonin. Histamine produced similar dilatory effects (about 200 dyn) in both types of arteries and competitive inhibitions were obtained with burimamide, showing that the dilation was mediated through histamine H2 receptors. Dissociation constants were calculated for the receptor-antagonist complex.

Animals↗
PubMed1975

Preservation of estrogen-induced increase of uterine blood volume following catechlamine and mast cell histamine depletion.

Uterine blood volume increases after administration of estrogen to ovariectomized mice. The effect on uterine blood volume was not altered by depletion of mast cell histamine with compound 48/80 or by depletion of norepinephrine from uterine nerves by 6-hydroxydopamine. Thus, neither reduction in the adrenergic transmitter content nor release of mast cell histamine appears to play any primary role in mediating the changes in uterine hemodynamics produced by estrogen, at least as they are reflected by changes in uterine blood volume.

Animals↗
PubMed1975

[Amine receptors in brain vessels].

Isolated middle cerebral arteries from cats and pial arteries from humans (obtained during lobe resection) were studied in a sensitive in vitro system allowing a detailed pharmacological characterization of various amine receptors and related dissociation constants. It was found that the adrenergic receptors comprise contractile (alpha) and dilatory (beta) receptors. Acetylcholine induced dilation (at low doses) as well as constriction (at high doses) both responses being inhibited in a comparative way by atropine. Experiments with selective inhibitors showed the presence of specific histamine H2 (dilatory) receptors; at high doses histamine contracted the vessels in a non-specific way. 5-Hydroxytryptamine was the most efficient vasoconstrictor agent, and the response could be blocked by the serotonin-antagonist, methysergide.

Acetylcholine↗
PubMed1975

Mechanical response in the wall of ovarian follicles mediated by adrenergic receptors.

The identity of the adrenergic receptors involved in the contractility of the follicular wall was studied in bovine ovaries. Strips were prepared mainly from the protruding part of large Graafian follicles and mounted in an organ bath for recording of mechanical activity. Some intact ovaries and strips from the bottom of follicles were also studied. The latter two preparations showed spontaneous rhythmic contractions, and the tension was increased by norepinephrine and reduced by terbutaline. Norepinephrine, epinephrine, phenylephrine, isoproterenol and terbutaline alone or in combination with various concentrations of the inhibitors, phenoxybenzamine, piperoxan and propranolol, were used to analyze adrenoceptors in strips from the protruding portion of the follicle. Such strips showed no appreciable spontaneous contractions. A contractile response was found to be mediated by alpha receptors. The KA value for norepinephrine (determined in combination with phenoxybenzamine) was found to be 2.26 X 10- minus 6 M and KB for piperoxan (determined in combination with norepinephrine) was 1.02 X 10-minus 8 M (pA2 = 8.19). Adrenergic beta receptors mediated relaxation of the strips, and the KB value for propranolol (determined in combination with terbutaline) was 7.28 X 10-minus 9 M (pA2 = 8.17).

Adrenergic alpha-Antagonists↗