Adrenergic and cholinergic innervation of the atrioventricular valves in chinchilla (Chinchilla laniger)

The arrangement of autonomic fibres was studied in the cardiac atrioventricular valves of small chinchillas. The dissected valves were stained entirely using the modified histochemical acetylcholine esterase technique (AChE) and the SPG-De la Torre method. Double immunocytochemical staining was also used for the expression of vesicular acetylcholine transporter (VAChT) and dopamine beta hydroxylase (DBH). The study showed the presence of both cholinergic and adrenergic fibres, forming a kind of network on all cusps of both valves. The adrenergic network is always more strongly represented than the cholinergic network. The cholinergic nerve network of the "parietal" part formed mainly the parallel arrangement. As we move towards the free parts of the cusps, the arrangement becomes netted and radiant. The adrenergic fibres formed only the netted arrangement, which was the most dense in the peripheral (parietal) part of the cusps. Some of the fibres in the vicinity of tendinous cords extended as far as the papillary muscles. Double immunocytochemical tests confirmed the presence and distribution of DBH- and VAChT-positive fibres. Some fibres (especially within the tendinous cords) show VAChT and DBH colocalisation.

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