L X Sha | PubMed Health

PubMed1995

Suppression of macrophage reactive intermediates by cocaine.

The in vivo or in vitro effects of cocaine on the production of hydrogen peroxide (H2O2), superoxide (O2-), and nitrite (NO2-) by sodium periodate-elicited macrophages were studied. Hydrogen peroxide and superoxide productions were suppressed by both in vitro treatments and in vivo administrations of cocaine. The H2O2 and O2- production partially recovered after 150 min in vitro. However, cocaine inhibited NO2- production only in vitro, failing to suppress it through in vivo administration.

Animals↗

PubMed1994

Adrenergic receptors regulate macrophage secretion.

Macrophages have been shown to possess both alpha 2 and beta 2-adrenergic receptors which appear to antagonize each other. The ability of these two kinds of receptors to mediate macrophage secretion was tested, using alpha- and beta-antagonists, idazoxan and propranolol. Both antagonists could inhibit hydrogen peroxide and superoxide secretion, although the timing of the inhibition is different. However, only idazoxan has the ability to reduce nitrite accumulation, while propranolol fails to affect macrophage production. In addition, sodium nitrite was able to inhibit hydrogen peroxide and superoxide secretion, and hydrogen peroxide could reduce nitrite accumulation, suggesting that a negative cross-feedback mechanism exists.

Adrenergic alpha-Antagonists↗