PKG protein of porcine coronary arteries following 24 h incubation with NTG (a, b), DETA NO (c) or 8-Br-cGMP or 8-bromo-adenosine 3′5′-cyclic monophosphate (d). The upper panels are western blots of PKG. The lower panels are the densitometric scanning of PKG protein normalized to actin. NTG, 10−5 M unless otherwise stated; DETA NO,10−5 M; 8-Br-cGMP or 8- 8-bromo-adenosine 3′5′-cyclic monophosphate, 10−5 M; ODQ, 3 × 10−5 M; PKG-I, (Rp-8-Br-PET-cGMPS), 3 × 10−5 M. Data shown as means±s.e.mean; n=4–6 for each group. *Significantly different from the control group; †significantly different from vessels incubated with NTG (b) or incubated with DETA NO (c) (P<0.05). 8-Br-cGMP, 8-bromo-guanosine 3′5′-cyclic monophosphate; DETA NONOate, [2,2′-(hydroxynitrosohydrazono) bis(ethanamine)]; NTG, nitroglycerine; ODQ, 1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one; PKG, cGMP-dependent protein kinase.