Evidence for a pyloro-cholecystic reflex for gallbladder contraction

Area of Science:

• Gastroenterology
• Neurogastroenterology
• Digestive Physiology

Background:

• The antrum's role in upper gastrointestinal function is primarily attributed to gastrin release.
• Neural mechanisms coordinating digestive processes are increasingly recognized.

Purpose of the Study:

• To investigate the effect of antral distension on gallbladder contraction.
• To determine if gastrin release is essential for this response.
• To elucidate the neural pathways involved in antrum-gallbladder signaling.

Main Methods:

• Utilized five dogs with innervated antral pouches, chronic bile fistulas, and gastric fistulas.
• Administered graded alkaline (promoting gastrin) and acid (blocking gastrin) antral distension.
• Assessed gallbladder contraction via bilirubin output.
• Investigated the role of cholinergic pathways using parenteral atropine and truncal vagotomy.

Main Results:

• Graded antral distension induced graded gallbladder contraction, even when gastrin release was suppressed.
• This non-gastrin mediated gallbladder contraction was abolished by atropine and vagotomy.
• Evidence supports a cholinergic, pyloro-cholecystic reflex dependent on vagal pathways.

Conclusions:

• The stomach antrum integrates upper gastrointestinal function via both hormonal (gastrin) and neural reflex mechanisms.
• A cholinergic, pyloro-cholecystic reflex, initiated by antral distension, contributes to gallbladder contraction.
• Antral distension also triggers other neural reflexes, such as pyloro-pancreatic and pyloro-oxyntic reflexes.