Fig. 1.

Schematic representation of protocols. Intrathecal injections (arrows) of saline or drugs dissolved in saline are indicated by arrows. After surgical procedures, rats were allowed to recover from anesthesia for 60 min before beginning experimental protocols. The first 2 contractions (CTX; gray boxes) were used to verify the viability of the preparation to express the exercise pressor reflex upon hindlimb muscle contraction. Subsequent contractions (black boxes) were used to examine the effect of the drug on the exercise pressor reflex. Series of contractions were separated by intervals of time (white boxes). DAMGO, [d-Ala²,N-MePhe⁴,Gly-ol]-enkephalin; GVIA,  ω-conotoxin-GVIA; TLQ, tertiapin-LQ; no inj,  no injection.