Long-term incubation of clonal neural cell lines with ethanol differentially reduces the stimulation of cAMP accumulation by hormones and cholera toxin. In the NG108-15 neuroblastoma chi glioma hybrid cell line, this heterologous desensitization was associated with a 42% reduction in the expression of Gs alpha and no significant change in Gi alpha. By contrast, ethanol treatment of the parental neuroblastoma cell line N18TG2 caused little loss of response to hormones or cholera toxin and no significant change in Gs alpha or Gi alpha. Ethanol induced heterologous desensitization in N1E-115 neuroblastoma cells; however, this cell line showed a dose-dependent increase in Gi alpha and a later decrease in Gs alpha. Thus, ethanol causes heterologous desensitization of hormone-stimulated cAMP accumulation by different mechanisms in related neural cell lines.