Figure 3. Representative chart recordings showing gastric contraction (A) and relaxation (B) produced by microinjection of PrRP into the rostral DMV and caudal portion of the DMV, respectively, and elimination of the gastric motor response to peptide administration following ipsilateral vagotomy.

A, microinjection of PrRP (2 pmol/20 nL) into the rostral portion of the right DMV evoked a marked increase in IGP. Following ipsilateral vagotomy, administration of PrRP in the same site had no effect on IGP (third trace from left). Microinjection of the same dose of PrRP into the corresponding site in the DMV on the contralateral (left) side produced a large increase in IGP despite prior sectioning of the right vagus nerve. B, in another rat, microinjection of PrRP (2 pmol (20 nl)⁻¹) into the left DMV at the level of the CS induced a sustained decrease in IGP and inhibited phasic contractions. IGP returned to the baseline level abruptly upon sectioning of the ipsilateral vagus nerve (second trace from left), whereas a subsequent injection of the peptide at the same site made 45 min after vagotomy did not affect IGP. In contrast, microinjection of PrRP into a similar location within the caudal DMV on the contralateral (right) side induced gastric relaxation (trace at far right).