Behavioral economics of polysubstance use: The role of orexin-1 receptors in nicotine-induced augmentation of synthetic opioid consumption.
Study Goal
The researchers aimed to determine how developmental nicotine exposure and acute nicotine administration affect motivation for opioid consumption, particularly through the orexin system.
Results Summary
The study found that adolescent nicotine exposure (ANE) increased motivation for opioid consumption in adulthood, which was further exacerbated by acute nicotine administration (ANA). ORX1R antagonism was more effective in reducing opioid motivation in nicotine-exposed rats compared to controls.
Population
Rodents (rats)
Effective Dosage
Not specified
Duration
Not specified
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
ongoing nicotine administration | increase | opioid consumption | rodents and humans | - | facilitates | #1 |
former exposure to nicotine solely during adolescence | increase | opioid consumption | - | - | augments | #2 |
adolescent nicotine exposure (ANE) | increase | multiple indices of the motivational value of RMF | rats | - | augment | #3 |
acute nicotine administration (ANA) | increase | effects of ANE on motivational value of RMF | rats | - | exacerbated | #4 |
systemic antagonism of ORX1Rs with SB-334867 | decrease | motivation for RMF | nicotine-exposed rats | - | more efficacious in limiting | #5 |
systemic antagonism of ORX1Rs with SB-334867 | decrease | limiting motivation for RMF | rats in ANA conditions | - | differential efficacy was even greater | #6 |
Nicotine and opioid use disorders are highly comorbid in clinical populations. Ongoing nicotine administration facilitates opioid consumption in both rodents and humans. Moreover, preclinical studies support that former exposure to nicotine solely during adolescence augments opioid consumption in adulthood similarly to acute nicotine administration. This suggests that developmental nicotine exposure persistently alters the neural substrates underlying motivation in a manner that resembles the acute pharmacological actions of nicotine. The orexin system mediates motivation to consume opioids in large part through signaling at orexin-1 receptors (ORX1Rs). Both developmental nicotine exposure and acute nicotine administration profoundly alter functioning of the orexin system which may mediate the reinforcing enhancing properties of nicotine. Here, we used behavioral economic procedures to generate demand curves for consumption of the synthetic, short-acting, μ-opioid receptor agonist remifentanil (RMF) in adulthood following prior adolescent nicotine exposure (ANE) and again following reintroduction of acute nicotine administration (ANA). We found that ANE was sufficient to augment multiple indices of the motivational value of RMF in adulthood and these effects were further exacerbated by ANA given during RMF self-administration sessions. Additionally, we demonstrate that systemic antagonism of ORX1Rs with SB-334867 is more efficacious in limiting motivation for RMF in nicotine-exposed rats relative to controls and this differential efficacy was even greater in ANA conditions relative to former ANE. These findings support that nicotine-induced facilitation of orexin signaling may mechanistically contribute to augmented opioid consumption offering critical insight for treatment options for a population that is particularly vulnerable to developing opioid use disorder.