engleski

Immunohistochemical diversity of vagal afferent neurons in the rat heart

Aim: To determine the neurochemical phenotype of afferent neurons projecting to different parts of the rat heart, both atria and ventricles. Methods: Experiments were performed on 16 three-month-old female Sprague Dawley rats. Each animal had only one Fast Blue (FB) "patch" applied to a different part of the heart. Multiple immunohystochemical stainings were performed, for detection of neurofilament heavy chains (N52), calretinin (CALR) as well as for presence of isolectin B4 (IB4) on FB- labeled neurons in both right and left nodose ganglia for each animal. Results: Only around one hundred neurons per ganglion were labeled with FB representing about 2% of total number of nodose ganglia neurons. Among all FB labeled neurons projecting to different parts of the heart, around 50% were N52+ and 16% were IB4+. Out of all neurons projecting to atria and ventricles, 10% and 33% were calretinin- immunoreactive, respectively. There were approximately 30% of negative neurons. Colocalization was found only in 2% of IB4 and N52, and in 4% of IB4 and CALR positive neurons. Conclusion: Considering the afferent vagal innervation of the rat heart we identified eight different neuronal subgroups (IB4+/N52-, IB4+/N52+, IB4-/N52-, IB4-/N52+, IB4+/CALR-, IB4+/CALR+, IB4-/CALR-, IB4- /CALR+). Neurons projecting to all parts of the heart have similar neurochemical phenotypes, in regard to N52 and IB4 staining, whereas the difference exist in CALR immunostaining between atria and ventricles.

nodose ganglion; rat heart; immunohistochemistry

Broj 23