Is vagal stimulation or inhibition benefit on the regulation of the stomach brain axis in obesity?

ABSTRACT

Objective: Possible effects of the vagus inhibition and stimulation on the hypothalamic nuclei, myenteric plexes and the vagus nerve were investigated.

Methods: The female rats divided to the inhibition (INH), stimulation (STI) and, sham (SHAM) groups were fed with high fat diet (including 40% of energy from animal fat). After nine weeks, the rats were allowed to recover for 4 weeks in INH group. In STI group, the left vagus nerve stimulated (30 Hz/500 msn/30 sec.) starting 2nd post operative day for 5 minutes during 4 weeks. Healthy female rats used as control (CONT). Then, tissue samples were analyzed by biochemical, histological and stereological methods.

Results: The mean number of the neurons in the arcuate nucleus of the INH group was significantly less; but, that is significantly more in the STI group compared to the other groups. The neuronal density of ventromedial nucleus in the STI group was higher; while the density in the INH group was lower than the other groups. In the dorsomedial nucleus, neuron density of the INH group was lower than the other groups. In terms of the myenteric plexus volumes, that of the INH group was lowest. The myelinated axon number in the INH group was significantly highest. The myelin sheath thickness and axon area of the INH group was significantly lower than the other groups.

Discussion: The results of the study show that the vagal inhibition is more effective than the vagal stimulation on the weight loss in the obesity.

KEYWORDS:

• Obesity
• vagal stimulation
• vagal inhibition
• hypothalamic nuclei
• POMC
• NPY
• myenteric plexus

Disclosure statement

No potential conflict of interest was reported by the author(s).

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by funds from the Turkish Scientific Reaearch Concil (TUBITAK) by number of 214S614.

Notes on contributors

Işınsu Alkan

Işınsu Alkan is postdoctoral researcher in the Dept. of Histology and Embryology, Medical School, Istanbul Okan University; İstanbul/Turkey. She obtained PhD degree from Ondokuz Mayıs University, Samsun/Turkey. Her research focuses on diet interactions with the gut-brain axis and brain health.

Berrin Zuhal Altunkaynak

Berrin Zuhal Altunkaynak is full professor in the Dept. of Histology and Embryology, Medical School, Istanbul Okan University; İstanbul/Turkey. She previously studied by associated and assistant professor titles in Ondokuz Mayıs University, Samsun/Turkey. Her research focuses on the effects of the diets on metabolizm.

Elfide Gizem Kivrak

Elfide Gizem Kivrak is assistant professor in the Dept. of Histology and Embryology, Medical School, Adıyaman University; Adıyaman/Turkey. She obtained PhD degree from Ondokuz mayıs University, Samsun/Turkey. Her research focuses on electromagnetic field and brain.

Arife Ahsen Kaplan

Arife Ahsen Kaplan is PhD student in the Dept. of Histology and Embryology, Medical School, Medipol University; İstanbul/Turkey. She previously studied as research assistant and obtained master degree in Ondokuz Mayıs University, Samsun/Turkey. Her research focuses on neuroscience.

Gülay Arslan

Gülay Arslan was master student in the Dept. of Histology and Embryology, Medical School, Ondokuz Mayıs University, Samsun/Turkey. She freezed their academic studies and married. Now, she is growing her son.