M1 muscarinic receptor is a key target of neuroprotection, neuroregeneration and memory recovery by i-Extract from Withania somnifera

Sci Rep. 2019 Sep 30;9(1):13990. doi: 10.1038/s41598-019-48238-6.

Abstract

Memory loss is one of the most tragic symptoms of Alzheimer's disease. Our laboratory has recently demonstrated that 'i-Extract' of Ashwagandha (Withania somnifera) restores memory loss in scopolamine (SC)-induced mice. The prime target of i-Extract is obscure. We hypothesize that i-Extract may primarily target muscarinic subtype acetylcholine receptors that regulate memory processes. The present study elucidates key target(s) of i-Extract via cellular, biochemical, and molecular techniques in a relevant amnesia mouse model and primary hippocampal neuronal cultures. Wild type Swiss albino mice were fed i-Extract, and hippocampal cells from naïve mice were treated with i-Extract, followed by muscarinic antagonist (dicyclomine) and agonist (pilocarpine) treatments. We measured dendritic formation and growth by immunocytochemistry, kallikrein 8 (KLK8) mRNA by reverse transcription polymerase chain reaction (RT-PCR), and levels of KLK8 and microtubule-associated protein 2, c isoform (MAP2c) proteins by western blotting. We performed muscarinic receptor radioligand binding. i-Extract stimulated an increase in dendrite growth markers, KLK8 and MAP2. Scopolamine-mediated reduction was significantly reversed by i-Extract in mouse cerebral cortex and hippocampus. Our study identified muscarinic receptor as a key target of i-Extract, providing mechanistic evidence for its clinical application in neurodegenerative cognitive disorders.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Western
  • Dendrites / drug effects
  • Dendrites / physiology
  • Dicyclomine / pharmacology
  • Female
  • Male
  • Memory / drug effects*
  • Mice
  • Mice, Transgenic
  • Nerve Regeneration / drug effects*
  • Neuroprotective Agents / pharmacology*
  • Pilocarpine / pharmacology
  • Plant Extracts / pharmacology*
  • Receptor, Muscarinic M1 / agonists
  • Receptor, Muscarinic M1 / antagonists & inhibitors
  • Receptor, Muscarinic M1 / drug effects*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Scopolamine / pharmacology
  • Withania / chemistry*

Substances

  • Neuroprotective Agents
  • Plant Extracts
  • Receptor, Muscarinic M1
  • Pilocarpine
  • Dicyclomine
  • Scopolamine