Neurotransmitters and neuromodulators released by contraction‐activated skeletal muscle afferents into the dorsal horn of the spinal cord initiate the central component of the exercise pressor reflex (EPR). Evidence suggests that transmission at this synapse is mainly mediated by excitatory amino acids (i.e., glutamate). However, whether GABA, a major inhibitory neurotransmitter within the mammalian central nervous system, is involved in the modulation of the EPR at the level of the dorsal horn remains to be determined. To test this hypothesis, we performed local microinjection of either the GABA(A) antagonist bicuculline or the GABA(B) antagonist CGP 52432 into the ipisilateral L4/L5 dorsal horns to determine the effect of these GABA receptor antagonists on the pressor response to either static contraction induced by stimulation of the peripheral end of L4/L5 ventral roots or passive stretch in decerebrate rats. We found that microinjection of either bicuculline (1 mM, 100 nl) or CGP 52432 (10 mM, 100 nl) into the L4/5 dorsal horns significantly increased the pressor and cardioaccelerator responses to either static contraction or passive stretch in decerebrate rats. Data are presented in the table. In addition, microinjection of these two antagonists also caused a temporary increase in the baseline blood pressure and heart rate which returned to normal level in 2–3 min. These data suggest that GABA evokes a tonic inhibition of the EPR at the level of dorsal horn in spinal cord.