Ultrastructural Morphometry of the Aortic Depressor Nerves and Extrinsic Renal Nerves: Similarities and Differences between Mice and Ratsda Silva Carvalho C1, Sato KL2,3, Castania JA4, Salgado HC4, Nessler RA3 and Fazan VPS1,3,5*
- *Corresponding Author:
- Valeria Paula Sassoli Fazan, M.D., Ph.D
Associate Professor, Department of Surgery and Anatomy
School of Medicine of Ribeirao Preto
USP, Av. Bandeirantes 3900, Ribeirao Preto
SP, Brazil, 14049-900
Tel: +55 16 3602-4634
Fax: +55 16 3633-0017
E-mail: [email protected]; [email protected]
Received date: April 14, 2014; Accepted date: May 23, 2014; Published date: May 25, 2014
Citation: da Silva Carvalho C, Sato KL, Castania JA, Salgado HC, Nessler RA (2014) Ultrastructural Morphometry of the Aortic Depressor Nerves and Extrinsic Renal Nerves: Similarities and Differences between Mice and Rats. Anat Physiol 4:142. doi: 10.4172/2161-0940.1000142
Copyright: © 2014 da Silva Carvalho, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Anatomical and physiological aspects involving rats and mice have shown similarities and differences between these experimental animal models. In cardiovascular physiology research, rats are being substituted by mice since mice are more susceptible to genetic manipulation. Nevertheless, little is known about mice normal anatomy and/or physiology to allow the correct interpretation of altered responses on genetically manipulated animals. We compared morphometric ultrastructural parameters of the aortic depressor nerve (ADN) and extrinsic renal nerve (SRN) between Wistar rats and C57BL/6J mice. After spontaneous activity recordings together with the arterial pressure pulse, ADN and SRN were dissected and prepared for light and transmission electron microscopy. Morphometry was performed with an image analysis software and took into consideration the fascicle area and diameter, myelinated and unmyelinated fiber number, density, area and diameter, myelin sheath area and the g-ratio. Comparisons were made for the same nerve between mice and rats and differences were considered significant when p<0.05. Both nerves were large in rats compared to mice, as were the myelinated fibers. On the other hand, unmyelinated fibers density, size and distributions were not different between species. These results suggest physiological differences on the fast conduction fibers between species, with possible different functional role. Morphological comparisons of the quantitative composition of peripheral nerves in different species and strains are very rare. Our study contributes to a morphological understanding of important nerves related to cardiovascular reflexes in two animal models. It also presents, for the first time, ultrastructural morphometric characteristics of the ADN in mice. This data provide a morphological basis for further studies involving functional investigations for reflex regulation of circulation in experimental model of hypertension and to improved cardiovascular system knowledge.