TY - JOUR
T1 - MLR stimulation and exercise pressor reflex activate different renal sympathetic fibers in decerebrate cats
AU - Hayes, Shawn G.
AU - Kaufman, Marc P.
PY - 2002
Y1 - 2002
N2 - Although mesencephalic locomotor region (MLR) stimulation and the exercise pressor reflex have been shown to increase whole nerve renal sympathetic activity, it is not known whether these mechanisms converge onto the same population of renal sympathetic postganglionic efferents. In decerebrate cats, we examined the responses of single renal sympathetic postganglionic efferents to stimulation of the MLR and the exercise pressor reflex (i.e., static contraction of the triceps surae muscles). We found that, in most instances (24 of 28 fibers), either MLR stimulation or the muscle reflex, but not both, increased the discharge of renal postganglionic sympathetic efferents. In addition, we found that renal sympathetic efferents that responded to static contraction while the muscles were freely perfused responded more vigorously to static contraction during circulatory arrest. Moreover, stretch of the calcaneal (Achilles) tendon stimulated the same renal sympathetic efferents as did static contraction. These findings suggest that MLR stimulation and the exercise pressor reflex do not converge onto the same renal sympathetic postganglionic efferents.
AB - Although mesencephalic locomotor region (MLR) stimulation and the exercise pressor reflex have been shown to increase whole nerve renal sympathetic activity, it is not known whether these mechanisms converge onto the same population of renal sympathetic postganglionic efferents. In decerebrate cats, we examined the responses of single renal sympathetic postganglionic efferents to stimulation of the MLR and the exercise pressor reflex (i.e., static contraction of the triceps surae muscles). We found that, in most instances (24 of 28 fibers), either MLR stimulation or the muscle reflex, but not both, increased the discharge of renal postganglionic sympathetic efferents. In addition, we found that renal sympathetic efferents that responded to static contraction while the muscles were freely perfused responded more vigorously to static contraction during circulatory arrest. Moreover, stretch of the calcaneal (Achilles) tendon stimulated the same renal sympathetic efferents as did static contraction. These findings suggest that MLR stimulation and the exercise pressor reflex do not converge onto the same renal sympathetic postganglionic efferents.
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U2 - 10.1152/japplphysiol.00905.2001
DO - 10.1152/japplphysiol.00905.2001
M3 - Article
C2 - 11896030
AN - SCOPUS:0036093009
SN - 8750-7587
VL - 92
SP - 1628
EP - 1634
JO - Journal of applied physiology
JF - Journal of applied physiology
IS - 4
ER -