piperidines and buflomedil

In vitro studies on the action of buflomedil (BFL) and its derivative CRL 41034 on the polymorphonuclear cells (PMN) has been performed using functional tests and scanning electron microscopy. The two drugs exhibited the same effects. BFL does not change the in vitro chemotaxis of PMN, but exhibits a regulatory effect on ZMS-induced aggregation of these cells. BFL also appeared to decrease superoxide production of PMN, in a dose- and time-dependent way. The cytoskeleton F-actin polymerization, analyzed through the binding of rhodamin-phalloidin, was increased when the total F-actin of the cells was unchanged. When cell extensions were studied morphologically a change in the shape of the pseudopods as well as the general aspect of the PMN (cottonous aspect) was observed as compared to controls. These drug-induced modifications in the shape change may be efficient in adhesion processes. Finally this latter effect and the influence on oxygen metabolite production could be another means of BFL to protect the microvessels during ischemia, in addition to its vasomotion promoting properties.

Topics: Actins; Cell Aggregation; Chemotaxis, Leukocyte; Cytoskeleton; Humans; Microscopy, Electron, Scanning; N-Formylmethionine Leucyl-Phenylalanine; Neutrophils; Piperidines; Pyrrolidines; Superoxides; Vasodilator Agents

Experiments were designed to determine the effect of CRL 41034, a buflomedil analogue, on the adrenergic responsiveness of canine veins. Rings of saphenous vein (without endothelium) were suspended for isometric tension recording in modified Krebs-Ringer bicarbonate solution at 37 degrees C. CRL 41034 produced a concentration-dependent inhibition of the contractions evoked by the alpha adrenergic agonists norepinephrine, phenylephrine and UK 14304 which was insensitive to the blockade of neuronal uptake by cocaine. CRL 41034 was more potent in inhibiting the concentration-dependent contractions evoked by UK 14304 than those by phenylephrine and the antagonism it caused against the response to UK 14304 fulfilled the criteria for competitivity. CRL 41034, at 10(-5) M significantly depressed, and at 10(-4) M abolished the contractions induced by electrical stimulation of the adrenergic nerves and those evoked by the indirect sympathomimetic amine tyramine. Strips of canine saphenous vein were superfused after incubation with [3H] norepinephrine. During sympathetic nerve activation, CRL 41304 increased the stimulation-evoked overflow of [3H] norepinephrine and 3-methoxy-4-dihydroxyphenylglycol; in the presence of rauwolscine the compound only increased the stimulation-evoked overflow of 3,4-dihydroxyphenylglycol. These experiments suggest that the major vascular effects of CRL 41034 in canine veins are blockade of alpha 2-adrenoceptors on vascular smooth muscle, and inhibition of prejunctional alpha 2-adrenoceptors on adrenergic nerve endings.

Topics: Adrenergic alpha-Agonists; Adrenergic alpha-Antagonists; Animals; Brimonidine Tartrate; Dogs; Electric Stimulation; Female; Isometric Contraction; Male; Norepinephrine; Phenylephrine; Piperidines; Pyrrolidines; Quinoxalines; Saphenous Vein