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Ontogeny of low threshold myelinated vagal afferents in the rat is sexually dimorphic.
Author(s) -
Qian Zhao,
Li BaiYan,
Schild John
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.720.2
Subject(s) - ontogeny , sexual dimorphism , biology , endocrinology , population , medicine , anatomy , neuroscience , environmental health
We have previously reported on the existence of a sex‐specific subpopulation of low threshold myelinated vagal afferents. These “Ah‐type” fibers are rarely found in male rats and exhibit an excitability profile strongly influenced by circulating sex hormones. Postnatally, these “Ah‐type” afferents are present in both sexes but by adulthood Ah‐type visceral afferents have nearly disappeared from the male population. This study aims to quantify the time course of the differential ontogenetic development of Ah‐type afferents using the patch clamp technique. Current clamp protocols were carried out on vagal ganglion neurons (VGN) acutely dissociated from 4, 6, 8, 11, 13, 15, 21, 23, 25, 28, 30, 32 day old rats of both sexes. A cluster analysis of select measures from the current clamp recordings revealed three statistically unique populations of VGN at each time point, low threshold myelinated A‐ and Ah‐type VGN and high threshold unmyelinated C‐type VGN. The relative expression of these three afferent subtypes in females remains relatively steady from 4 – 32 days. In stark contrast, the relative expression of Ah‐type afferents in males declines from levels comparable to those in female at birth to a near absence in adulthood. Our results quantify the time course of visceral afferent ontogeny and provide additional support for our hypotheses regarding sexual dimorphism in visceral afferent function. HL072012 HL081819