Cannabidiol Differentially Modulates Synaptic Release and Cellular Excitability in Amygdala Subnuclei

Cannabidiol (CBD) is a non-psychoactive constituent of the Cannabis plant that has purported effectiveness in treating an array of stress-related neuropsychiatric disorders. The amygdala is a subcortical brain structure that regulates emotional behavior, and its dysfunction has been linked to numerous disorders including anxiety and posttraumatic stress disorder. Despite this, the direct effects of CBD on synaptic and cellular function in the amygdala are not known. Using electrophysiology and pharmacology, we report that CBD reduces presynaptic neurotransmitter release in the amygdala, and these effects are dependent on subnucleus and cell type. Furthermore, CBD broadly decreases cellular excitability across amygdala subnuclei. These data reveal physiological mechanisms by which CBD modulates amygdala activity and could provide insights into how CBD could affect emotional and stress-related behavioral responses.

Use of aequorin-based indicators for monitoring Ca2+ in acidic organelles

Over the last years, there is accumulating evidence that acidic organelles can accumulate and release Ca²⁺ upon cell activation. Hence, reliable recording of Ca²⁺ dynamics in these compartments is essential for understanding the physiopathological aspects of acidic organelles. Genetically encoded Ca²⁺ indicators (GECIs) are valuable tools to monitor Ca²⁺ in specific locations, although their use in acidic compartments is challenging due to the pH sensitivity of most available fluorescent GECIs. By contrast, bioluminescent GECIs have a combination of features (marginal pH sensitivity, low background, no phototoxicity, no photobleaching, high dynamic range and tunable affinity) that render them advantageous to achieve an enhanced signal-to-noise ratio in acidic compartments. This article reviews the use of bioluminescent aequorin-based GECIs targeted to acidic compartments. A need for more measurements in highly acidic compartments is identified.

New insights from nanotechnology in SARS-CoV-2 detection, treatment strategy, and prevention

The recent outbreak of SARS-CoV-2 resulted into the deadly COVID-19 pandemic, which has made a profound impact on mankind and the world health care system. SARS-CoV-2 is mainly transmitted within the population via symptomatic carriers, enters the host cell via ACE2 and TMPSSR2 receptors and damages the organs. The standard diagnostic tests and treatment methods implemented lack required efficiency to beat SARS-CoV-2 in the race of its spreading. The most prominently used diagnostic test,reverse transcription-polymerase chain reaction (a nucleic acid-based method), has limitations including a prolonged time taken to reveal results, limited sensitivity, a high rate of false negative results, and lacking specificity due to a homology with other viruses. Furthermore, as part of the treatment, antiviral drugs such as remdesivir, favipiravir, lopinavir/ritonavir, chloroquine, daclatasvir, atazanavir, and many more have been tested clinically to check their potency for the treatment of SARS-CoV-2 but none of these antiviral drugs are the definitive cure or suitable prophylaxis. Thus, it is always required to combat SARS-CoV-2 spread and infection for a better and precise prognosis. This review answers the above mentioned challenges by employing nanomedicine for the development of improved detection, treatment, and prevention strategies for SARS-CoV-2. In this review, nanotechnology-based detection methods such as colorimetric assays, photothermal biosensors, molecularly imprinted nanoparticles sensors, electrochemical nanoimmunosensors, aptamer-based biosensors have been discussed. Furthermore, nanotechnology-based treatment strategies involving polymeric nanoparticles, metallic nanoparticles, lipid nanoparticles, and nanocarrier-based antiviral siRNA delivery have been depicted. Moreover, SARS-CoV-2 prevention strategies, which include the nanotechnology for upgrading personal protective equipment, facemasks, ocular protection gears, and nanopolymer-based disinfectants, have been also reviewed. This review will provide a one-site informative platform for researchers to explore the crucial role of nanomedicine in managing the COVID-19 curse more effectively.

Opposing retrograde and astrocyte-dependent endocannabinoid signaling mechanisms regulate lateral habenula synaptic transmission

The lateral habenula (LHb) encodes aversive states, and its dysregulation is implicated in neuropsychiatric disorders, including depression. The endocannabinoid (eCB) system is a neuromodulatory signaling system that broadly serves to counteract the adverse effects of stress; however, CB1 receptor signaling within the LHb can paradoxically promote anxiogenic- and depressive-like effects. Current reports of synaptic actions of eCBs in the LHb are conflicting and lack systematic investigation of eCB regulation of excitatory and inhibitory transmission. Here, we report that eCBs differentially regulate glutamatergic and GABAergic transmission in the LHb, exhibiting canonical and circuit-specific inhibition of both systems and an opposing potentiation of synaptic glutamate release mediated via activation of CB1 receptors on astrocytes. Moreover, simultaneous depression of GABA and potentiation of glutamate release increases the net excitation-inhibition ratio onto LHb neurons, suggesting a potential cellular mechanism by which cannabinoids may promote LHb activity and subsequent anxious- and depressive-like aversive states.