The effect of selectively denervating portions of the myenteric plexus on g
astroduodenal (GD) motility was examined in domestic turkeys (Meleagris gal
lopavo). The neural network beneath the lateral or medial side of the isthm
us between the glandular stomach and the muscular stomach was denervated by
application of 1% benzalkonium chloride (BC). Image intensification radiol
ogy (IIR) was performed postsurgically on the research subjects to observe
GD contractions and to analyze aberrations. Two trials were performed. The
first employed temporal controls by checking GD motility in all treated bir
ds before and after BC had taken effect. The second trial controlled for th
e trauma associated with the surgical procedure by applying 0.9% saline sol
ution in lieu of BC in four turkeys. The normal GD contractions sequence as
confirmed by these controls was thin muscle contraction, duodenal contract
ion and outflow, thick muscle contraction, and, finally, glandular stomach
contraction. Ablation of the nerves beneath the medial or lateral side of t
he isthmus resulted in the same abnormality in GD motility, namely a lack o
f thick muscle contractions. These results indicate that the entire myenter
ic plexus associated with the isthmus must remain intact for proper GD moti
lity to take place. Furthermore, it can be inferred that initiation and reg
ulation of the thick muscle pair acts via nerves encircling the isthmus. Se
condary regulatory mechanisms controlling GD motility may exist and should
be tested through future investigation.