Biologia, Bratislava 54/Suppl. 6: 221-225, 1999.

ISSN 0006-3088 (Biologia). ISSN 1335-6399 (Biologia. Section Cellular and Molecular Biology).


Full paper

Distribution of NADPH-diaphorase activity in the tricuspid valve of the rat.


Kvetuse Lovasova*, Katarina Schmidtova, Darina Kluchova, Maria Miklosova, Sylvia Rybarova, Monika Kocisova & Frantisek Dorko

Department of Anatomy, Faculty of Medicine, P. J. Safarik University, Srobarova 2, SK-04001 Kosice, Slovakia; tel.: ++421 95 6228866, e-mail:

* corresponding author

Received: January 7, 1999 / Accepted: October 5, 1999



A histochemical technique was used to investigate the neuronal structures that show NADPH-diaphorase activity in the valva tricuspidalis in the heart. This technique involved whole-mount stretch preparations of the valves, enabling the study of their innervation pattern by means of light microscopy. Whole-mount valves provide an extremely useful means to study the occurrence of nerve fibres, their distribution and their interrelationships in the tricuspid valve. The highest concentrations of NADPH-diaphorase positive nerve fibres and fibres in the tunica adventitia of the arterial wall were found in the basal zone of the tricuspid valve adjacent to the fibromuscular atrioventricular ring. In the intermediate zone of the valve, very few nerve fibres were found. These nerve fibres had a vertical course and they ended directly as free nerve endings. In the distal parts of the valve short nerve fibres were found, again in the vertical course. The fibres did not reach either the free margin of the valve cusps or the chordae tendineae.


Key words: tricuspid valve, NADPH-diaphorase, nitric oxide, innervation, vessels, rat.