Heme oxygenase-2 and nitric oxide synthase in guinea-pig intracardiac neurones.
There is increasing evidence that carbon monoxide (CO), like nitric oxide (NO), may be a neuronal messenger molecule. This study investigated the expression of heme oxygenase-2 (HO-2), the enzyme responsible for the synthesis of CO, by intracardiac neurones. Many, if not all newborn guinea-pig intracardiac neurones in culture were HO-2-immunoreactive. Furthermore, double labelling showed that a relatively small subpopulation of these neurones also expressed NO synthase/nicotinamide dinucleotide phosphate (NADPH)-diaphorase (NOS/NADPH-d) activity. These findings suggest that intracardiac neurones can synthesize CO and that CO may be fundamental to their function. Comparison of the proportions of intracardiac neurones that contain HO-2 with those that express NOS/NADPH-d activity also indicates that CO may be more important than NO in the intrinsic neuronal control of the heart.
Hassall
C J
CJ
Department of Anatomy and Developmental Biology, University College London, UK.
Hoyle
C H
CH
D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D006168:Guinea Pigs; D006321:Heart / Q000294:innervation*; D006325:Heart Atria; D006419:Heme Oxygenase (Decyclizing) / Q000032:analysis*; D007150:Immunohistochemistry; D009457:Neuroglia / Q000166:cytology / Q000201:enzymology; D009474:Neurons / Q000166:cytology / Q000201:enzymology*; D019001:Nitric Oxide Synthase / Q000032:analysis*
D019001:Nitric Oxide Synthase; D006419:Heme Oxygenase (Decyclizing); C105245:heme oxygenase-2