European Journal of Pharmacology
October 25, 2025
Satoshi Deyama, Kenji Mishiro, Munetaka Kunishima et al.
A single injection of (R)-ketamine at 30 mg/kg, but not 10 mg/kg, reduced marble burying—a measure of compulsive-like behavior—in male mice at 2 hours, 24 hours, and 7 days after treatment, without affecting general movement. (S)-ketamine at 10 mg/kg also reduced burying. Blocking L-type voltage-dependent calcium channels (L-VDCCs) with verapamil prevented the effect of (S)-ketamine but not of (R)-ketamine. Infusing verapamil directly into the ventromedial orbitofrontal cortex or ventromedial prefrontal cortex also blocked (S)-ketamine's effect. These findings suggest (R)-ketamine produces anticompulsive-like effects comparable to a 3-fold lower dose of (S)-ketamine, and that L-VDCC activation in those brain regions mediates the effects of (S)-ketamine but not (R)-ketamine.
Neuropsychopharmacology reports
March 1, 2025
Naoya Nishitani, Yuki Sasaki, Katsuyuki Kaneda
MDMA, a recreational drug known for prosocial effects, was studied in mice to examine how it affects neural activity in the nucleus accumbens (NAc) during social behaviors. Using fiber photometry, researchers measured NAc activity while mice interacted with novel mice. NAc activity transiently increased at the onset of turning toward and sniffing novel mice, though turning was infrequent. MDMA reduced the duration of sniffing per bout but did not alter the transient NAc activity at the onset of these social behaviors, suggesting the drug does not affect this specific neural response.
Psychopharmacology
July 1, 2019
Shiho Ito, Satoshi Deyama, Masaki Domoto et al.
The synthetic cannabinoid 5F-AMB, when injected into the brain of mice, reduces anxiety and impairs the acquisition of recognition memory by activating CB1 receptors. Systemic injection severely reduces movement, an effect partially blocked by a CB1 antagonist. Infusion into the medial prefrontal cortex impairs memory acquisition but does not affect anxiety, suggesting other brain regions mediate the anxiolytic effect.
Psychopharmacology
August 1, 2018
Masaki Domoto, Hitoki Sasase, Shintaro Wada et al.
5F-AMB, a synthetic cannabinoid abused worldwide, reduces both excitatory and inhibitory signaling in layer V pyramidal neurons of the medial prefrontal cortex by activating CB1 receptors on presynaptic terminals. Bath application of 5F-AMB decreased the frequency of spontaneous and miniature excitatory and inhibitory postsynaptic currents, an effect blocked by the CB1 antagonist AM251. The suppression of excitatory transmission was greater than that of inhibitory transmission, shifting the balance toward net inhibition of these neurons. This inhibitory effect may contribute to the memory and consciousness impairments observed after inhalation of 5F-AMB.