Pharmacology, Biochemistry and Behavior
December 9, 2019
Satoshi Deyama, R. Duman
181 citations
Depression is linked to reduced levels of neurotrophic factors like BDNF and VEGF, which contribute to neuronal atrophy in brain regions such as the prefrontal cortex and hippocampus, and to decreased adult neurogenesis. Conventional antidepressants partially reverse these deficits by inducing BDNF or VEGF but have limitations, including a delayed therapeutic response and low efficacy. Ketamine, an NMDA receptor antagonist, produces rapid (within hours) and sustained (up to a week) antidepressant effects in treatment-resistant depression and rodent models. In rodents, ketamine quickly increases BDNF and VEGF release in the medial prefrontal cortex and hippocampus, boosting spine synapses and hippocampal neurogenesis. These neurotrophic actions appear to underlie ketamine's rapid and sustained antidepressant effects, pointing toward development of faster-acting antidepressants with fewer side effects.
Pharmacology, Biochemistry and Behavior
June 1, 2019
Lijia Chang, Kai Zhang, Yaoyu Pu et al.
174 citations
In a mouse model of chronic social defeat stress, a single intranasal dose of (R)-ketamine produced stronger antidepressant effects than (R,S)-ketamine or (S)-ketamine. Conversely, (S)-ketamine caused the greatest increase in locomotor activity and deficits in prepulse inhibition, followed by (R,S)-ketamine, while (R)-ketamine showed the least. In conditioned place preference tests, repeated intranasal (S)-ketamine and (R,S)-ketamine increased preference scores dose-dependently, indicating abuse liability, whereas (R)-ketamine did not. These findings suggest intranasal (R)-ketamine may be a safer antidepressant option.
Pharmacology, Biochemistry and Behavior
February 5, 2020
Yan Wei, Lijia Chang, K. Hashimoto
157 citations
The antidepressant effects of (R,S)-ketamine, a mixture of (R)-ketamine and (S)-ketamine, are a major advance in mood research. Off-label use for treatment-resistant depression has grown in the US, and in 2019 the FDA and European authorities approved (S)-ketamine nasal spray for this condition, but only in certified medical settings. Preclinical evidence indicates that (R)-ketamine may be more potent and longer-lasting as an antidepressant than (S)-ketamine, with fewer side effects. Clinical trials of (R)-ketamine in humans are now underway. This article reviews the history of these compounds and discusses the mechanisms behind ketamine's antidepressant actions.
Pharmacology, Biochemistry and Behavior
April 22, 2020
J. Witkin, J. Kranzler, K. Kaniecki et al.
33 citations
The (R)-ketamine enantiomer may offer a safer treatment for substance abuse disorder by reducing withdrawal symptoms and drug-seeking behavior without causing negative mood or anhedonia. In experiments with morphine-dependent rats, (R)-ketamine alleviated withdrawal signs and blocked morphine-induced place preference in mice without producing place preference itself. Unlike S-ketamine, (R)-ketamine did not induce anhedonia in rats. These findings suggest (R)-ketamine could dampen withdrawal and drug liking without the dissociative or mood-related side effects that limit current therapies, supporting further preclinical and clinical investigation.