Gastric vagotomy inhibits drinking after hypertonic saline

Area of Science:

• Neuroscience
• Physiology
• Gastroenterology

Background:

• The vagus nerve plays a crucial role in regulating physiological functions, including thirst and satiety.
• Cellular dehydration, induced by hypertonic saline, typically triggers a drinking response.
• Previous studies indicated that bilateral subdiaphragmatic vagotomy impairs this drinking response.

Purpose of the Study:

• To pinpoint the specific vagal nerve pathways responsible for the reduced drinking response to cellular dehydration.
• To determine if selective vagotomies (gastric, hepatic, or coeliac) replicate the effects of total vagotomy on drinking behavior.

Main Methods:

• Rats underwent selective vagotomies: gastric, hepatic, or coeliac, or total bilateral subdiaphragmatic vagotomy.
• Control groups included sham-operated rats.
• Drinking responses were measured after administration of 0.15 M and 1 M NaCl solutions.

Main Results:

• Rats with gastric vagotomy exhibited drinking deficits similar to those with total vagotomy.
• Hepatic and coeliac vagotomies did not significantly alter the drinking response to hypertonic saline.
• Gastric vagal fiber disconnection was identified as the critical factor.

Conclusions:

• Disconnection of gastric vagal fibers is both necessary and sufficient to reduce the drinking response to hypertonic saline.
• This highlights the specific role of the gastric vagus nerve in mediating thirst regulation during cellular dehydration.