Immediate and Persistent Effects of Salvinorin A on the Kappa Opioid Receptor in Rodents, Monitored In Vivo with PET.
Michael S. Placzek, Genevieve C Van de Bittner, Hsiao‐ying Wey, Scott E Lukas, Jacob M Hooker
Neuropsychopharmacology December 1, 2015 DOI: 10.1038/npp.2015.159 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Experimental study with PET imaging Peer reviewed |
|---|---|
| Sample size | 31 |
| Population | Male Sprague-Dawley rats |
| Intervention | Salvinorin A |
| Dose | 0.01-1.8 mg/kg, i.v. |
| Topics | Salvia divinorum |
| Key findings | At 0.60 mg/kg, salvinorin A induced a sustained decrease in KOR binding (BPND decreased by 40-49%) that persisted up to 2.5 hours after the drug had been eliminated from the brain. |
Abstract
Monitoring changes in opioid receptor binding with positron emission tomography (PET) could lead to a better understanding of tolerance and addiction because altered opioid receptor dynamics following agonist exposure has been linked to tolerance mechanisms. We have studied changes in kappa opioid receptor (KOR) binding availability in vivo with PET following kappa opioid agonist administration. Male Sprague-Dawley rats (n=31) were anesthetized and treated with the (KOR) agonist salvinorin A (0.01-1.8 mg/kg, i.v.) before administration of the KOR selective radiotracer [(11)C]GR103545. When salvinorin A was administered 1 min prior to injection of the radiotracer, [(11)C]GR103545 binding potential (BPND) was decreased in a dose-dependent manner, indicating receptor binding competition. In addition, the unique pharmacokinetics of salvinorin A (half-life ~8 min in non-human primates) allowed us to study the residual impact on KOR after the drug had eliminated from the brain. Salvinorin A was administered up to 5 h prior to [(11)C]GR103545, and the changes in BPND were compared with baseline, 2.5 h, 1 h, and 1 min pretreatment times. At lower doses (0.18 mg/kg and 0.32 mg/kg) we observed no prolonged effect on KOR binding but at 0.60 mg/kg salvinorin A induced a sustained decrease in KOR binding (BPND decreased by 40-49%) which persisted up to 2.5 h post administration, long after salvinorin A had been eliminated from the brain. These data point towards an agonist-induced adaptive response by KOR, the dynamics of which have not been previously studied in vivo with PET.
Comparable studies
Other preclinical and animal studies on salvia divinorum, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Effects of the plant-derived hallucinogen salvinorin A on basal dopamine levels in the caudate putamen and in a conditioned place aversion assay in mice: agonist actions at kappa opioid receptors. Mice | 2005 | Experimental study | |
| Potential anxiolytic‐ and antidepressant‐like effects of salvinorin A, the main active ingredient of Salvia divinorum, in rodents Male Sprague-Dawley rats and male Albino Swiss mice | 2009 | Experimental study | |
| Involvement of kappa-opioid and endocannabinoid system on Salvinorin A-induced reward. Wistar rats | 2008 | Experimental study | |
| Role of kappa-opioid receptors in the effects of salvinorin A and ketamine on attention in rats. Rats | 2010 | Experimental study | |
| The plant-derived hallucinogen, salvinorin A, produces kappa-opioid agonist-like discriminative effects in rhesus monkeys. Rhesus monkeys | 2004 | Experimental study | n = 3 |
Citations in the library
Cites 12
- Salvinorin A: a potent naturally occurring nonnitrogenous kappa opioid selective agonist. Proceedings of the National Academy of Sciences September 3, 2002
- Divinorin A, a psychotropic terpenoid, and divinorin B from the hallucinogenic Mexican mint, Salvia divinorum The Journal of Organic Chemistry November 1, 1984
- Dose-related effects of salvinorin A in humans: dissociative, hallucinogenic, and memory effects. Psychopharmacology March 1, 2013
- Human psychopharmacology and dose-effects of salvinorin A, a kappa opioid agonist hallucinogen present in the plant Salvia divinorum. Drug and Alcohol Dependence May 1, 2011
- Neuropharmacology of the naturally occurring kappa-opioid hallucinogen salvinorin A. Pharmacological Reviews June 1, 2011
and 7 more in the library