title: Femoral artery ligation increases the responses of thin-fiber muscle afferents to contraction.
abstract: Previous evidence has shown that ligating the femoral artery for 72 h resulted in an exaggerated exercise pressor reflex. To provide electrophysiological evidence for this finding, we examined in decerebrated rats whose femoral arteries were either freely perfused or ligated for 72 h the responses of thin-fiber (i.e., groups III and IV) afferents to static contraction of the hindlimb muscles. We found that contraction increased the combined activity of group III and IV afferents in both freely perfused (n = 29; baseline: 0.3 ± 0.1 imp/s, contraction: 0.8 ± 0.2 imp/s; P < 0.05) and ligated rats (n = 28; baseline: 0.4 ± 0.1 imp/s, contraction: 1.4 ± 0.1 imp/s; P < 0.05). Most importantly, the contraction-induced increase in afferent activity was greater in ligated rats than it was in freely perfused rats (P = 0.005). In addition, the responses of group III afferents to contraction in ligated rats (n = 15; baseline 0.3 ± 0.1 imp/s, contraction 1.5 ± 0.2 imp/s) were greater (P = 0.024) than the responses to contraction in freely perfused rats (n = 18; baseline 0.3 ± 0.1 imp/s, contraction 0.9 ± 0.2 imp/s). Likewise, the responses of group IV afferents to contraction in ligated rats (n = 13; baseline 0.5 ± 0.1 imp/s, contraction 1.3 ± 0.2 imp/s) were greater (P = 0.048) than the responses of group IV afferents in freely perfused rats (n = 11; baseline 0.3 ± 0.1 imp/s, contraction 0.6 ± 0.2 imp/s). We conclude that both group III and IV afferents contribute to the exaggeration of the exercise pressor reflex induced by femoral artery ligation.
authors: Heart and Vascular Institute, Penn State College of Medicine, Hershey, Pennsylvania astone1@hmc.psu.edu.
authors: Audrey J
authors: AJ
authors: Stone
authors: Heart and Vascular Institute, Penn State College of Medicine, Hershey, Pennsylvania.
authors: Steven W
authors: SW
authors: Copp
authors: Heart and Vascular Institute, Penn State College of Medicine, Hershey, Pennsylvania.
authors: Jennifer L
authors: JL
authors: McCord
authors: Heart and Vascular Institute, Penn State College of Medicine, Hershey, Pennsylvania.
authors: Marc P
authors: MP
authors: Kaufman
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D005263:Femoral Artery / Q000502:physiology*; D008026:Ligation / Q000379:methods*; D008297:Male; D009119:Muscle Contraction; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
keywords: group III and IV afferents; peripheral artery disease; sympathetic activity during exercise