Treatment of cultured human astrocytes with gp120 (which can be secreted by infected cells during infection) resulted in an increased rate of ethidium uptake, while inhibition of Cx43 channels by preincubation with two different Cx43 mimetic peptides (Tat-L2 or gap19) blocked this effect, suggesting gp120 triggered an increase in hemichannel activity in these cells. The gene discussed is GJA1; the disease is infection.