Partial left ventricular ischemia in isolated hearts obtained from ethanol-dependent rats

Histamine inhibits IL-4 secretion from T helper type 2 cells but enhances IL-5 secretion from the same cells. Both of these effects are mediated by H₂ receptors. Not all cyclic AMP-elevating agents affect IL-4 and IL-5 secretion. The observations suggest a selective effect of histamine on TH₂ lymphocytes. Furthermore, Cl^- channels may be involved in histamine-mediated regulation of cytokine secretion. The data suggest that histamine-induced elevation of cyclicAMP may be an important, but probably not the sole, mechanism underlying the selective effects of histamine on cytokine production.