In cultured guinea pig SAN cells, where active Pak1 expression was induced through infection with recombinant adenovirus expressing constitutively active Pak1 (CA-Pak1), responses of both L-type Ca2+ channel (LTCC) and delayed rectifier K+ channel currents to β-adrenergic stimulation by isoproterenol were depressed in comparison to SAN cells infected with control virus, Ad-LacZ. The gene discussed is PAK1; the disease is infection.