Effects of medullary alpha2-adrenoceptor blockade in the rat.

The effect of alpha2-adrenoceptor blockade in the medulla was studied in pentobarbital anesthetized rats in which arterial blood pressure, heart rate and renal sympathetic nerve activity were analysed. Three series of experiments were performed: (1) i.c.

Synthesis and biological evaluation of new tetrahydronaphthalene derivatives as thromboxane receptor antagonists.

New polysubstituted tetrahydronaphthalene derivatives were prepared as thromboxane receptor (TP-receptor) antagonists. Within this series of compounds S 18886 has been identified as an orally active, highly potent antagonist with a very long duration of action in different species.

Recording of the saphenous vein compliance by an ultrasonic echo-tracking device in the dog: effects of S 18149.

1. Saphenous vein reactivity was recorded in the anaesthetized dog by use of an ultrasonic echo-tracking device to measure the internal diameter of the vein and to calculate the venous compliance. This method was used to investigate the effects of a new partial alpha1/alpha2-adrenoceptor agonist, S 18149, on the canine saphenous vein in vivo after intravenous (i.

(S)-spiro[(1,3-diazacyclopent-1-ene)-5,2'-(7'-methyl-1',2',3',4'- tetrahydronaphthalene)]: resolution, stereospecific synthesis, and preliminary pharmacological characterization as a partial alpha-adrenergic agonist.

Recently, we reported on the design, synthesis, and structure-activity relationships of a series of spiroimidazolines endowed with alpha-adrenergic agonist activities. Among the compounds described, (R,S)-spiro(1,3-diazacyclopent-1-ene)-[5,2'](7'-methyl-1'2',3', 4',-tetrahydronaphthalene) fumarate (5RS) was chosen for further development as a venotonic agent. The resolution of this compound, as well as the pharmacological characterization of the enantiomers, stereospecific synthesis of eutomer (5S, S 18149), and determination of absolute configuration by single-crystal X-ray diffraction analysis, are described.

The central sympatho-inhibitory effect of 5,6-dihydroxy-2-dimethylaminotetralin (M7) is mediated by alpha 2-adrenoceptors.

M7 (5,6-dihydroxy-2-dimethylaminotetralin) produces in anesthetized rats a hypotensive response previously attributed to peripheral dopaminergic mechanisms. We re-examined the effects of this drug on arterial blood pressure, heart rate and sympathetic nerve activity in anesthetized rats and dogs. M7 (1-100 micrograms/kg i.