# The Microbiome in opioid use and abuse

> **NIH NIH R21** · UNIVERSITY OF CALIFORNIA AT DAVIS · 2020 · $241,710

## Abstract

Summary
Currently we are faced with a significant conundrum with regard to the opioid crises. On the one hand, we have
no viable alternative for treating severe post-surgical and chronic pain. On the other hand, people taking these
drugs for legitimate purposes are transitioning at an alarming rate to opioid overuse and abuse. While the
dramatic increase in opioid abuse has coincided with the much-reported increase in opioid prescriptions, it is still
true that only a fraction of patients who are prescribed opioids for pain transition to abuse. If we could identify
those pain patients most at risk prior to opioid treatment, we could potentially stem the tide of opioid abuse. A
number of compelling studies have recently shown that alterations in the gut microbiome can influence a plethora
of central nervous systems disorders, leading to widespread acceptance of the concept of a gut-microbiome-
brain axis. We find it compelling that, coincident with the increase in opioid prescriptions, there has also been a
large increase in the routine and often unnecessary use of oral antibiotics—a trend that that has altered the gut
microbiome of an entire generation. Not surprisingly, given the widespread expression of opioid receptors in the
gut, opioids have been shown to alter the gut microbiome. Furthermore, alterations in the microbiome have been
shown to alter opioid analgesia and reward, suggesting that opioids influence the gut-brain axis. However, to
date, no studies have examined whether the gut microbiome influences abuse liability. Here we will capitalize
on both behavioral variability in a mouse model of compulsive drug seeking and relapse, and mouse microbiome
variability, both innate and in response to morphine, to determine whether abuse liability and the microbiome co-
vary (Aim 1). We will also examine whether the microbiome from an “addict” mouse or “non-addict” mouse can
predispose to or protect subjects from compulsive drug seeking or relapse (Aim 2). This project is a dual Principal
Investigator proposal that capitalizes on the complementary expertise of two experts in their respective fields,
one a molecular microbiologist the other an opioid pharmacologist.

## Key facts

- **NIH application ID:** 9999769
- **Project number:** 1R21DA049565-01A1
- **Recipient organization:** UNIVERSITY OF CALIFORNIA AT DAVIS
- **Principal Investigator:** CHERYL ALLYNE WHISTLER
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $241,710
- **Award type:** 1
- **Project period:** 2020-06-01 → 2022-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9999769

## Citation

> US National Institutes of Health, RePORTER application 9999769, The Microbiome in opioid use and abuse (1R21DA049565-01A1). Retrieved via AI Analytics 2026-05-21 from https://api.ai-analytics.org/grant/nih/9999769. Licensed CC0.

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