Fig. 5. In preparations in which the stn was intact, the muscarinic acetylcholine agonist oxotremorine enhanced ongoing pyloric activity. (A) Recordings of pyloric activity in a representative preparation in control saline, during superfusion of 10^–6 mol l^–1 oxotremorine, and during the wash with normal saline. Oxotremorine enhanced the overall pyloric pattern, seen most clearly here as an increase in pyloric cycle frequency and as increased activity in the PD (pdn and lvn) and VD (mvn) neurons. (B) Phase diagram, showing two cycles of the activity of the pyloric pattern in control saline. (C) Phase diagram of the pyloric pattern when the STG was superfused with 10^–6 mol l^–1 oxotremorine. (D) Plot of the cycle period in both control saline and oxotremorine, showing the decreased cycle period during oxotremorine application. (E,F) Graphs of spike frequency during bursts and burst duration, respectively, in each of the pyloric neuronal types in control saline and when the STG was being superfused with oxotremorine. N=5 for all graphs. Bars indicate standard deviations. Asterisks indicate a value significantly different from control (P<0.05). Nerves: mvn, medial ventricular nerve (recording action potentials of the VD and IC neurons); pdn, pyloric dilator nerve (recording action potentials of the PD neurons); lvn, lateral ventricular nerve (recording action potentials of the PD, LP and PY neurons).