Digital autoradiography for efficient functional imaging without anesthesia in experimental animals: Reversing phencyclidine-induced functional alterations using clozapine

Nitrous oxide induces hypothermia and TrkB activation: Maintenance of body temperature abolishes antidepressant-like effects in mice

Recent studies indicate that nitrous oxide (N2O), a gaseous anesthetic and an NMDA (N-methyl-D-aspartate) receptor antagonist, produces rapid antidepressant effect in patients suffering from treatment-resistant depression. Our recent work implies that hypothermia and reduced energy expenditure are connected with antidepressant-induced activation of TrkB neurotrophin receptors - a key regulator of synaptic plasticity. In this study, we demonstrate that a brief exposure to N2O leads to a drop in body temperature following the treatment, which is linked to decreased locomotor activity; enhanced slow-wave electroencephalographic activity; reduced brain glucose utilization; and increased phosphorylation of TrkB, GSK3β (glycogen synthase kinase 3β), and p70S6K (a kinase downstream of mTor (mammalian target of rapamycin)) in the medial prefrontal cortex of adult male mice. Moreover, preventing the hypothermic response in a chronic corticosterone stress model of depression attenuated the antidepressant-like behavioral effects of N2O in the saccharin preference test. These findings indicate that N2O treatment modulates TrkB signaling and related neurotrophic signaling pathways in a temperature-dependent manner, suggesting that the phenomenon driving TrkB activation - altered thermoregulation and energy expenditure - is linked to antidepressant-like behavioral responses.

111Ag phantom images with Cerenkov Luminescence Imaging and digital autoradiography within the ISOLPHARM project

Targeted Radionuclide Therapy (TRT) is a medical technique exploiting radionuclides to combat cancer growth and spread. TRT requires a supply of radionuclides that are currently produced by either cyclotrons or nuclear research reactors. In this context, the ISOLPHARM project investigates the production of innovative radionuclides for medical applications. This production will be based on the forthcoming SPES facility at the Legnaro National Laboratories (LNL) of the National Institute for Nuclear Physics (INFN), an ISOL facility where high-purity radioactive beams will be used to produce carrier-free radiopharmaceuticals. Previous studies demonstrated that a significant amount of 111Ag, an innovative β/γ emitter suitable for TRT with theranostic applications, can be obtained at the SPES facility. The present work describes the first imaging study on phantoms with 111Ag performed by the ISOLPHARM collaboration. This is a fundamental step to pave the way for the upcoming in vivo studies on the 111Ag-based radiopharmaceutical currently being developed. The imaging potential of this radionuclide was investigated by acquiring phantom images with Cerenkov Luminescence Imaging (CLI) and digital autoradiography (ARG).

Highlighting Functional Mass Spectrometry Imaging Methods in Bioanalysis

Most mass spectrometry imaging (MSI) methods provide a molecular map of tissue content but little information on tissue function. Mapping tissue function is possible using several well-known examples of "functional imaging" such as positron emission tomography and functional magnetic resonance imaging that can provide the spatial distribution of time-dependent biological processes. These functional imaging methods represent the net output of molecular networks influenced by local tissue environments that are difficult to predict from molecular/cellular content alone. However, for decades, MSI methods have also been demonstrated to provide functional imaging data on a variety of biological processes. In fact, MSI exceeds some of the classic functional imaging methods, demonstrating the ability to provide functional data from the nanoscale (subcellular) to whole tissue or organ level. This Perspective highlights several examples of how different MSI ionization and detection technologies can provide unprecedented detailed spatial maps of time-dependent biological processes, namely, nucleic acid synthesis, lipid metabolism, bioenergetics, and protein metabolism. By classifying various MSI methods under the umbrella of "functional MSI", we hope to draw attention to both the unique capabilities and accessibility with the aim of expanding this underappreciated field to include new approaches and applications.