# Mechanisms of RyR1 Modulation by General Anesthetics

> **NIH NIH R01** · UNIVERSITY OF PENNSYLVANIA · 2021 · $407,212

## Abstract

Description:
The skeletal muscle ryanodine receptor (RyR1) is a critical regulator of cellular calcium to facilitate
excitation contraction coupling. Mutations in this receptor underlie a number of serious disorders, one of
which is called malignant hyperthermia (MH). MH typically occurs unexpectedly during a general anesthetic,
and can be fatal. The intramolecular mechanism by which anesthetics modulate this receptor, or even if
they interact directly with RyR1, is completely unknown. For both wild type and MH mutant (R615C)
porcine RyR1, we will use photolabeling technology to determine whether and where two volatile
anesthetics, isoflurane and sevoflurane, bind (Aim 1); then reconcile these sites with the structure and
structural changes using cryo-electron microscopy (Aim 2). We will determine their single-channel effects on
ion transit using planar lipid bilayer electrophysiology (Aim 3). Finally, we will gauge relative binding affinity
among the expected multiple sites and which of these are most likely to be linked to functional effects, using
sophisticated computational approaches (equilibrium molecular dynamics and alchemical free energy
perturbation, Aim 4). We will test the effect of site-directed and natural mutations on binding affinity in
individual sites, which will then be iteratively tested by experiment in Aims 1 and 3. The included preliminary
data lends confidence for a successful outcome in each aim, and also has yielded surprising results in the
case of propofol, an injectable general anesthetic. The RyR1 is a challenging target due to its size and
complexity, but the technologies (photolabeling, mass spectrometry, cryo-electron microscopy, planar
bilayer electrophysiology, molecular dynamics) have matured to a point where this multidisciplinary
campaign has a very high probability of revealing the intramolecular mechanism of anesthetic modulation .

## Key facts

- **NIH application ID:** 10084299
- **Project number:** 5R01GM135633-02
- **Recipient organization:** UNIVERSITY OF PENNSYLVANIA
- **Principal Investigator:** Roderic G Eckenhoff
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $407,212
- **Award type:** 5
- **Project period:** 2020-01-10 → 2023-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10084299

## Citation

> US National Institutes of Health, RePORTER application 10084299, Mechanisms of RyR1 Modulation by General Anesthetics (5R01GM135633-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10084299. Licensed CC0.

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