Inhibition by intraventricular microinfusion of ketanserin of the cardiovascular responses to peripheral administration of methoxamine in rats.

The cardiovascular responses induced by intracerebroventricular or intravenous administration of ketanserin in normotensive rats were evaluated. Ketanserin, which is an antagonist at 5-HT2 receptors, when microinfused into the third cerebral ventricle, did not induce significant cardiovascular effects, except for a slight and transitory hypotensive response after the microinfusion of the highest dose (200 micrograms). However, at doses which were unable to affect directly blood pressure or heart rate, ketanserin, microinfused into the same site, antagonized the pressor response induced by peripheral administration of methoxamine, an alpha 1-adrenoceptor agonist.

Cultured astrocytoma cells inhibit platelet aggregation by releasing a nitric oxide-like factor.

Cultured astrocytoma cells were tested for their ability to generate a nitric-oxide like factor using platelet aggregation as a bioassay. Incubation of astrocytoma cells with human washed platelets resulted in an inhibition of thrombin-induced platelet aggregation which was proportional to the number of astrocytoma cells added. The inhibition was potentiated by superoxide dismutase (SOD) and prevented by oxyhaemoglobin (oxyHb).

The effects of phosphatidylserine on the decreased cardiovascular response to clonidine microinfused into the nucleus tractus solitarii of old rats.

1. The cardiovascular effects of direct microinfusions of clonidine into the nucleus tractus solitarii (NTS) in rats of different ages were studied. 2.

Effect of MN (III) tetrakis (4-benzoic acid) porphyrin by photodynamically generated free radicals on SODs keratinocytes.

Superoxide, a reactive form of oxygen, can be produced in vivo either in normal and under pathophysiologic conditions or by photosensitizing chemicals, as during photodynamic treatment. Photodynamic therapies (PDT), widely adopted in Dermatology and Oncology, are known to generate reactive oxygen species (ROS) and may contribute to structural alterations and oxidatively generated modifications of cellular antioxidants. We hypothesized that over-production of free radicals would decrease the enzymatic activities of endogenous cellular antioxidants.

Age-related alterations in cardiovascular responsiveness to clonidine infused into the nucleus tractus solitarii in rats.

The cardiovascular response to the unilateral injection of clonidine into the nucleus tractus solitarii in old compared to young rats was evaluated. In 3-month old rats clonidine (0.25, 0.