| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Physical Therapy, Exercise, and Nutrition Sciences, State University of New York at Buffalo, Buffalo, New York 14214-3079
Obesity is often associated with a reduced
ventilatory response and a decreased maximal exercise capacity. GABA is
a major inhibitory neurotransmitter in the mammalian central nervous
system. Altered GABAergic mechanisms have been detected in obese Zucker rats and implicated in their hyperphagic response. Whether altered GABAergic mechanisms also contribute to regulate ventilation and influence exercise capacity in obese Zucker rats is unknown and formed
the basis of the present study. Eight lean [317 ± 18 (SD) g]
and eight obese (450 ± 27 g) Zucker rats were studied at 12 wk of age. Ventilation at rest and ventilation during hypoxic (10%
O2) and hypercapnic (4% CO2) challenges were
measured by the barometric method. Peak O2 consumption
(
O2 peak) in response to a progressive
treadmill test to exhaustion was measured in a metabolic treadmill.
Ventilation and O2 peak were assessed
after administration of equal volumes of DMSO (vehicle) and the
GABAA receptor antagonist bicuculline (1 mg/kg). In lean animals, bicuculline administration had no effect on ventilation and
O2 peak. In obese rats, bicuculline
administration significantly (P < 0.05) increased
resting ventilation (465 ± 53 and 542 ± 72 ml · kg
1 · min1 for control
and bicuculline, respectively), ventilation during exposure to hypoxia
(899 ± 148 and 1,038 ± 83 ml · kg1 · min1 for control
and bicuculline, respectively), and
O2 peak (62 ± 3.7 and 67 ± 3.5 ml · kg0.75 · min1 for
control and bicuculline, respectively). However, in obese Zucker rats,
ventilation in response to hypercapnia did not change after bicuculline
administration (608 ± 96 vs. 580 ± 69 ml · kg1 · min1). Our
findings indicate that endogenous GABA depresses ventilation and limits
exercise performance in obese Zucker rats.
respiration; exercise; 
-aminobutyric acid; bicuculline; obesity
This article has been cited by other articles:
|
|
 |
|
  S.-D. Lee, W.-W. Kuo, D.-T. Bau, F.-Y. Ko, F.-L. Wu, C.-H. Kuo, F.-J. Tsai, P. S. Wang, M.-C. Lu, and C.-Y. Huang The coexistence of nocturnal sustained hypoxia and obesity additively increases cardiac apoptosis J Appl Physiol, April 1, 2008; 104(4): 1144 - 1153. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A.-L. Yang, M.-J. Lo, H. Ting, J.-S. Chen, C.-Y. Huang, and S.-D. Lee GABAA and GABAB receptors differentially modulate volume and frequency in ventilatory compensation in obese Zucker rats J Appl Physiol, January 1, 2007; 102(1): 350 - 357. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. V. S. Faustino and D. F. Donnelly An important functional role of persistent Na+ current in carotid body hypoxia transduction J Appl Physiol, October 1, 2006; 101(4): 1076 - 1084. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. D. Brutsaert, E. J. Parra, M. D. Shriver, A. Gamboa, M. Rivera-Ch, and F. Leon-Velarde Ancestry explains the blunted ventilatory response to sustained hypoxia and lower exercise ventilation of Quechua altitude natives Am J Physiol Regulatory Integrative Comp Physiol, July 1, 2005; 289(1): R225 - R234. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. K. Iyengar, C. M. Stein, K. Russo, B. O. Erokwu, and K. P. Strohl The fa leptin receptor mutation and the heritability of respiratory frequency in a Brown Norway and Zucker intercross J Appl Physiol, September 1, 2004; 97(3): 811 - 820. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Nakano, S.-D. Lee, and G. A. Farkas Dopaminergic modulation of ventilation in obese Zucker rats J Appl Physiol, January 1, 2002; 92(1): 25 - 32. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
