Journal of Isfahan Medical School

Journal of Isfahan Medical School

Involvement of Cholinergic Pathway in Energy Homeostasis via Ventromedial Hypothalamic D2 Receptors

Document Type : Original Article (s)

Authors
Maedeh Ghasemi 1
Nasrin Mehranfard 2
Mina Sadat Izadi 3
Atefeh Rayatpour 3
Hojjatallah Alaei 3
1 PhD in Physiology, Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
2 Assistant Professor, Neurophysiology Research Center, Urmia University of Medical Sciences, Urmia, Iran
3 MSc Student, Department of Physiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
10.22122/jims.v36i504.9819
Abstract
Background: Studies indicate that dopamine, particularly via D2 receptors (D2R), has an important role in energy homeostasis. Our previous study demonstrated that hypothalamic D2Rs, through dorsal vagus complex, are involved in the regulation of ghrelin secretion. In present study, we evaluated whether vagus cholinergic system could play a role in the regulation of leptin and glucose plasma levels by hypothalamic ventromedial nucleus (VMH) D2Rs?Methods: Canulation was performed into the VMH in Wistar rats (220-250 g). In experiment day, fasted rats (for 20-24 hours) received atropine (cholinergic antagonist, 5 mg⁄ kg subcutaneously) or saline. Thirty minutes later, D2R agonist (Quinpilroe, 0.5 µg) or antagonist (Sulpiride, 0.005 µg) and saline (0.5 µl) were injected into the VMH. Then, blood samples were collected 0, 30, and 60 minutes later, and plasma leptin and glucose levels were measured using enzyme-linked immunosorbent assay (ELISA) kit and glucose oxidase method, respectively.Findings: Plasma leptin significantly decreased in a time-dependent manner in atropine-Quinpirole group compared to control group (P < 0.001); while increase in glucose levels was time-dependently stable in atropine-Quinpirole group (P < 0.001). No significant change was observed in leptin levels in atropine-Sulpiride group compared to control group.Conclusion: VMHD2Rs exert their effects on the regulation of leptin and glucose levels, at least partly, via vagus cholinergic pathway.
Keywords
Ventromedial hypothalamic nucleus
Dopamine D2 receptors
Nonneuronal cholinergic system
Atropine
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Journal of Isfahan Medical School
Volume 36, Issue 504 - Serial Number 504
September and October 2019
Pages 1389-1394

  • Receive Date 16 March 2018
  • Accept Date 06 April 2022