OPEN Foundation

Day: 11 May 2017

Neuropathic and inflammatory antinociceptive effects and electrocortical changes produced by Salvia divinorum in rats

Abstract

ETHNOPHARMACOLOGICAL RELEVANCE:
Salvia divinorum is a medicinal plant traditionally used in hallucinogenic ethnopharmacological practices and for its analgesic and antinflammatory properties. Its active compounds include diterpenes known as salvinorins which act as potent κ opioid receptor agonists.
AIM OF THE STUDY:
Given its effects in acute animal models of pain, as well as its antinflammatory attributes, we decided to investigate the analgesic effects of an SD extract in neuropathic (sciatic loose nerve ligature) and inflammatory (intra plantar carrageenan) pain models in rats. We also determined in this study the electrocorticographic changes to correlate similar hallucinogenic state and behavior as those produced in humans.
MATERIAL AND METHODS:
Mechanical and thermonociceptive responses, plantar test and von Frey assay, respectively, were measured in adult Wistar rats 30min, 3h and 24h after the intraperitoneal administration of saline or an hydroponic SD extract. We also evaluated carbamazepine and celecoxib, as gold reference drugs, to compare its antinociceptive effects.
RESULTS:
Our results showed that administration of SD extract induced antialgesic effects in both neuropathic and inflammatory pain models. All those effects were blocked by nor-binaltorphimine (a Kappa opioid receptor antagonist). Moreover, it was observed an increase of the anterior power spectral density and a decrease in the posterior region as electrocorticographic changes.
CONCLUSION:
The present investigation give evidence that SD is capable to reduce algesic response associated to neuropathic and inflammatory nociception. This study support therapeutic alternatives for a disabling health problem due to the long term pain with high impact on population and personal and social implications.
Simón-Arceo, K., González-Trujano, M. E., Coffeen, U., Fernández-Mas, R., Mercado, F., Almanza, A., … & Pellicer, F. (2017). Neuropathic and inflammatory antinociceptive effects and electrocortical changes produced by Salvia divinorum in rats. Journal of Ethnopharmacology206, 115-124. 10.1016/j.jep.2017.05.016
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Dose-Related Effects of Adjunctive Ketamine in Taiwanese Patients with Treatment-Resistant Depression

Abstract

The antidepressant effects of ketamine are thought to depend on brain-derived neurotrophic factor (BDNF) genotype and dose. The purpose of this study was to characterize the dose-related antidepressant effects of ketamine in patients with treatment-resistant depression drawn from a Chinese population predominately possessing lower activity BDNF genotypes (Val/Met, Met/Met). We conducted a double-blind, randomized, parallel-group, placebo-controlled trial of a single ketamine infusion (saline, 0.2 mg/kg, 0.5 mg/kg). Patients (N=71; BDNF genotype: Val/Val (N=12, 17%), Val/Met (N=40, 56.3%), and Met/Met (N=19, 26.8%)) received mood ratings before infusion, after infusion, and for the subsequent 14 days. Plasma ketamine levels and BDNF genotypes were assessed. This study found a significant dose-related ketamine effect on scores on the Hamilton Depression Rating Scale (HAMD). The responder analysis (>50% reduction from baseline HAMD on at least 2 days between days 2 and 5) also revealed a significant dose-related effect (saline: 12.5%, 0.2 mg/kg: 39.1%; 0.5 mg/kg: 45.8%). This is the first report to our knowledge to demonstrate the dose-related efficacy of R/S-ketamine for treatment-resistant depression and the first to characterize ketamine effects in a genotyped Chinese population in which most (83%) patients possessed at least one copy of the lower functioning Met allele of the BDNF gene.
Su, T. P., Chen, M. H., Li, C. T., Lin, W. C., Hong, C. J., Gueorguieva, R., … & Krystal, J. H. (2017). Dose-Related Effects of Adjunctive Ketamine in Taiwanese Patients with Treatment-Resistant Depression. Neuropsychopharmacology. 10.1038/npp.2017.94
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Cognitive Behavior Therapy May Sustain Antidepressant Effects of Intravenous Ketamine in Treatment-Resistant Depression

Abstract

INTRODUCTION:
Ketamine has shown rapid though short-lived antidepressant effects. The possibility of concerning neurobiological changes following repeated exposure to the drug motivates the development of strategies that obviate or minimize the need for longer-term treatment with ketamine. In this open-label trial, we investigated whether cognitive behavioral therapy (CBT) can sustain or extend ketamine’s antidepressant effects.
METHODS:
Patients who were pursuing ketamine infusion therapy for treatment-resistant depression were invited to participate in the study. If enrolled, the subjects initiated a 12-session, 10-week course of CBT concurrently with a short 4-treatment, 2-week course of intravenous ketamine (0.5 mg/kg infused over 40 min) provided under a standardized clinical protocol.
RESULTS:
Sixteen participants initiated the protocol, with 8 (50%) attaining a response to the ketamine and 7 (43.8%) achieving remission during the first 2 weeks of protocol. Among ketamine responders, the relapse rate at the end of the CBT course (8 weeks following the last ketamine exposure) was 25% (2/8). On longer-term follow-up, 5 of 8 subjects eventually relapsed, the median time to relapse being 12 weeks following ketamine exposure. Among ketamine remitters, 3 of 7 retained remission until at least 4 weeks following the last ketamine exposure, with 2 retaining remission through 8 weeks following ketamine exposure. Ketamine nonresponders did not appear to benefit from CBT.
CONCLUSIONS:
CBT may sustain the antidepressant effects of ketamine in treatment-resistant depression. Well-powered randomized controlled trials are warranted to further investigate this treatment combination as a way to sustain ketamine’s antidepressant effects.
Wilkinson, S. T., Wright, D., Fasula, M. K., Fenton, L., Griepp, M., Ostroff, R. B., & Sanacora, G. (2017). Cognitive Behavior Therapy May Sustain Antidepressant Effects of Intravenous Ketamine in Treatment-Resistant Depression. Psychotherapy and Psychosomatics86(3), 162-167. 10.1159/000457960
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Addressing Structural Flexibility at the A-Ring on Salvinorin A: Discovery of a Potent Kappa-Opioid Agonist with Enhanced Metabolic Stability

Abstract

Previous structure-activity studies on the neoclerodane diterpenoid salvinorin A have demonstrated the importance of the acetoxy functionality on the A-ring in its activity as a κ-opioid receptor agonist. Few studies have focused on understanding the role of conformation in these interactions. Herein we describe the synthesis and evaluation of both flexible and conformationally restricted compounds derived from salvinorin A. One such compound, spirobutyrolactone 14, was synthesized in a single step from salvinorin B and had similar potency and selectivity to salvinorin A (EC50 = 0.6 ± 0.2 nM at κ; >10000 nM at μ and δ). Microsomal stability studies demonstrated that 14 was more metabolically resistant than salvinorin A. Evaluation of analgesic and anti-inflammatory properties revealed similar in vivo effects between 14 and salvinorin A. To our knowledge, this study represents the first example of bioisosteric replacement of an acetate group by a spirobutyrolactone to produce a metabolically resistant derivative.
Sherwood, A. M., Crowley, R. S., Paton, K. F., Biggerstaff, A., Neuenswander, B., Day, V. W., … & Prisinzano, T. E. (2017). Addressing Structural Flexibility at the A-Ring on Salvinorin A: Discovery of a Potent Kappa-Opioid Agonist with Enhanced Metabolic Stability. Journal of Medicinal Chemistry60(9), 3866-3878. 10.1021/acs.jmedchem.7b00148
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