Expression of hypoglossal long-term facilitation differs between substrains of Sprague-Dawley rat.
Long-term facilitation (LTF) is a prolonged, serotonin-dependent augmentation of respiratory motor output following episodic hypoxia. Previous observations lead us to hypothesize that LTF is subject to genetic influences and, as a result, differs between Sprague-Dawley (SD) rats from two vendors, Harlan (H) and Charles River Laboratories/Sasco (CRL/S). Using a blinded experimental design, we recorded integrated phrenic (integralPhr) and hypoglossal neurograms in anesthetized, vagotomized, paralyzed, and ventilated rats. At 60 min following three 5-min hypoxic episodes (Pa(O(2)) = 40 +/- 1 Torr; 5-min hyperoxic intervals), integralPhr was elevated from baseline in both SD substrains (i.e., LTF; P < 0.05). Conversely, hypoglossal LTF was present in CRL/S but not H rats (P < 0.05 between substrains). Serotonin immunoreactivity within the hypoglossal nucleus was not different between H and CRL/S rats. We conclude that the expression of hypoglossal LTF differs between SD rat substrains, indicating a difference in their genetic predisposition to neural plasticity.
Fuller
D D
DD
Department of Comparative Biosciences, University of Wisconsin, Madison, Wisconsin 53706, USA. fullerd@svm.vetmed.wisc.edu
Baker
T L
TL
Behan
M
M
Mitchell
G S
GS
D000818:Animals; D001784:Blood Gas Analysis; D005260:Female; D007002:Hypoglossal Nerve / Q000737:chemistry / Q000502:physiology*; D000860:Hypoxia / Q000503:physiopathology*; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D008297:Male; D009046:Motor Neurons / Q000502:physiology; D010791:Phrenic Nerve / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012143:Respiratory Physiological Phenomena; D012701:Serotonin / Q000032:analysis; D013045:Species Specificity
D012701:Serotonin