Psilocybin does not induce the vulnerability marker HSP70 in neurons susceptible to Olney's lesions.

S-ketamine, a N-methyl-D-aspartate receptor (NMDAR) antagonist, and psilocybin, a 5-hydroxy-tryptamine (serotonin) 2A receptor (5-HT2AR) agonist, are reported as effective rapid-acting antidepressants. Both compounds increase glutamate signalling and evoke cortical hyperexcitation. S-ketamine induces neurotoxicity especially in the retrosplenial cortex (Olney's lesions). Whether psilocybin produces similar neurotoxic effects has so far not been investigated. We performed an immunohistochemical whole-brain mapping for heat shock protein 70 (HSP70) in rats treated with psilocybin, S-ketamine, and MK-801. In contrast to S-ketamine- and MK-801-treated animals, we did not detect any HSP70-positive neurons in retrosplenial cortex of rats treated with psilocybin. Our results suggest that psilocybin might be safer for clinical use compared to S-ketamine regarding neuronal damage.

A systematic mapping review of the evolution of the rat Forced Swim Test: Protocols and outcome parameters.

As depression is projected to become the leading mental disease burden globally by 2030, understanding the underlying pathology, as well as screening potential anti-depressants with a higher efficacy, faster onset of action, and/or fewer side-effects is essential. A commonly used test for screening novel antidepressants and studying depression-linked aspects in rodents is the Porsolt Forced Swim Test. The present systematic mappping review gives a comprehensive overview of the evolution and of the most prevalently used set-ups of this test in rats, including the choice of animals (strain, sex, and age), technical aspects of protocol and environment, as well as reported outcome measures. Additionally, we provide an accessible list of all existing publications, to support informed decision-making for procedural and technical aspects of the test, to thereby enhance reproducibility and comparability. This should further contribute to reducing the number of unnecessarily replicated experiments, and consequently, reduce the number of animals used in future.

Aß-related Angiitis (ABRA)-A Rare Paraneoplastic Cause of Cerebral Vasculitis in a Young Patient: A Pathway From Unspecific Neurological Symptoms to Final Diagnosis.

INTRODUCTION: Aß-related angiitis (ABRA) is a very rare disease entity with combined features of cerebral amyloid angiopathy and primary angiitis of the CNS. However, the pathogenesis has not been conclusively described yet. Interestingly though, a possible paraneoplastic origin has been reported in the past. ABRA leads to severe encephalopathy with a broad spectrum of unspecific neurological symptoms and usually occurs in older patients. Because of the response to immunological treatment, it is important to confirm the diagnosis as fast as possible. Unfortunately, the pathway to a definite diagnosis is often complicated and prolonged. CASE REPORT: Here, we describe a 48-year-old-female patient presenting headache, behavioral changes as well as subacute fatigue and epileptic seizures in the recent past. The initial neuroradiological examination demonstrated extended lesions in the left hemisphere compatible with an inflammatory or neoplastic disease. After extensive investigations, initially without a definite result, we finally validated the diagnosis of ABRA by brain biopsy. Shortly afterwards a routine check-up revealed an invasive mammary carcinoma. Owing to a mandatory mastectomy and chemotherapy, an immunosuppressive therapy was not implemented. CONCLUSIONS: The reported case demonstrates our diagnostic approach and the clinical difficulties in validating a rare cause of encephalopathy in a young patient with nonspecific clinical and neuroradiological findings. Because of the possibility of an effective treatment, it is important to consider ABRA in the differential diagnosis especially when blood tests, analysis of cerebrospinal fluid, and angiography show normal results. Since a paraneoplastic genesis is presumed, a search for an underlying tumor disease should be considered.

CD8 T cell-Derived Perforin and TNF-α Are Crucial Mediators of Neuronal Destruction in Experimental Autoimmune Enteric Ganglionitis.

In neuron-specific ovalbumin-transgenic CKTAC mice, antigen-specific OT-I CD8 T cells home to the enteric nervous system, where they attack and destroy neurons of the myenteric and submucosal plexus. Clinically, experimental autoimmune enteric ganglionitis (EAEG) manifests with gastrointestinal dysmotility and rapidly progresses to lethal ileus. Although interferon-γ has been identified as capable of damaging neurons in EAEG, the role of perforin, Fas/FasL, and tumor necrosis factor-α (TNF-α) in this disease is still a matter of debate. Thus, CKTAC mice were adoptively transferred with either perforin-/- or wild-type OT-I CD8 T cells. In addition, CKTAC mice that had received wild-type OT-I CD8 T cells were treated by either anti-TNF-α or anti-FasL. Furthermore, wild-type OT-I CD8 T cells were adoptively transferred into CKTAC mice with neuron-specific deletion of Fas. Although neither inactivation of enteric neuronal Fas nor anti-FasL treatment improved the disease, the absence of perforin from OT-I CD8 T cells and anti-TNF-α treatment significantly ameliorated EAEG and prevented lethal ileus by rescue of enteric neurons. Thus, these experiments identify perforin and TNF-α as important in the pathogenesis of EAEG.