“Forskolin (1-300 microM), papaverine (1-100 microM), aminophylline (10-…-nitro-4-carboxyphenyl-N,N-diphenylcarbamate (10-300 microM), quinacrine (1-300 microM) and dibutyryl cyclic AMP (… almost equipotently in both contractile states whereas adenosine (10 microM-1 mM), sodium nitroprusside (10-… (100 microM-3 mM) were virtually ineffective.”