Participation of the medial septal area in salivation and dipsogenic response induced by pilocarpine injected peripherally

• Grant number: 20/04547-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2020
• End date: July 31, 2021
• Field of knowledge: Biological Sciences - Physiology - Physiology of Organs and Systems
• Principal Investigator: José Vanderlei Menani
• Grantee: Gabrieli Schiavon Marin
• Host Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

The study of sialagogue substances is of clinical interest because of their usefulness in patients with xerostomia. Cholinergic agonists stand out, pilocarpine being one of the most important. It induces salivation, injected peripherally and also water intake. The intracerebroventricular injection (icv) of muscarinic antagonists showed that the salivation produced by pilocarpine injected intraperitoneally (ip) depends on the activation of central muscarinic M3 receptors, while M1 and M2 receptors would participate in the water intake and pressure response, however, the responsible brain areas for these answers still need to be studied. 4-DAMP (M1 / M3 antagonist) injected into the medial septal area (ASM) reduces salivation induced by pilocarpine ip. Further tests combining pilocarpine ip with injection of specific antagonists of other types of muscarinic receptors in ASM are important to define the participation of ASM in the responses produced by pilocarpine ip and also to characterize the specific muscarinic receptors involved in these responses. Thus, the objective of the present project is to investigate the effects of the injection of specific M1, M2 and M4 receptor antagonists in ASM on salivation and ingestion of water produced by the injected pilocarpine ip. Holtzman rats with stain less steel cannulas implanted in ASM will be used. The effects of previous injections on ASM of pirenzepine (muscarinicantagonist M1), metoctramine (muscarinicantagonist M2 and M4) and tropicamide (muscarinicantagonist M4) on salivation and water intake induced by the ip injection of pilocarpine (1 mg / kg) body weight). Salivation will be measured in rats anesthetized with ketamine using previously weighed cotton balls placed in the oral cavity for 7 minutes. The volume of water ingested will be measured for 1 h after the ip injection of pilocarpine.