State-dependent and -independent effects of dialyzing excitatory neuromodulator receptor antagonists into the ventral respiratory column

The two major findings are as follows: 1) during unilateral dialysis of 50 mM atropine into the ventral respiratory column to block excitatory muscarinic receptor activity, a compensatory increase in other neuromodulators was state independent, but the ventilatory response appears to be state dependent; and 2) the hypothesis that absence of decreased Vi and f during unilateral dialysis of excitatory receptor antagonists was due to compensation by the contralateral VRC was not supported by findings herein.