Aortic depressor nerve morphometry in male and female adult spontaneously hypertensive rats.

Abstract

Previous studies form our laboratory [1,2] in spontaneously hypertensive rats (SHR) have demonstrated morphological alterations on the aortic depressor nerve (ADN), known to contain mainly barorreceptor fibers. Nevertheless, those studies used male and female rats indistinctly. We are investigating if there are morphological differences related to gender in the ADN of adult rats. Male and female SHR aged 20‐week were anesthetized for arterial pressure (AP) and heart rate (HR) recordings, together with the ADN spontaneous activity. After the recordings, the left ADN were prepared for light microscopy and morphometry. Comparisons were made between proximal and distal segments in the same gender and between genders. Males are significantly heavier than females but no differences in AP and HR between genders were found. There was a tendency towards larger fascicle values on males compared to females. Interestingly, this tendency was inverted on the myelinated fibers and respective axons sizes. Nevertheless, no significant differences were observed between genders on the morphometric parameters. We conclude that adult males and females can be used indistinctly for morphometric studies of the ADN if physiological parameters are similar between genders.