Solifenacin-induced acute psychosis: a case report

Solifenacin is a muscarinic receptor antagonist that has been used to treat overactive bladder since 2004. It has a great affinity for the detrusor M3 receptor, which must be stimulated for bladder muscle contraction, and demonstrates the most selective profile to the bladder of the muscarinic receptor subtypes. It is thought that urinary antimuscarinic agents, due to their passage to the central nervous system and lipophilic properties, may cause central nervous system symptoms in some rare cases. A case report of a 42-year-old male patient who had an acute psychotic attack as a result of solifenacin treatment for overactive bladder is presented in this article.

Salivary Lactoferrin Expression in a Mouse Model of Alzheimer’s Disease

In the last few years, microbial infection and innate immune theories have been proposed as an alternative approach explaining the etiopathogenesis and origin of Alzheimer’s disease (AD). Lactoferrin, one of the main antimicrobial proteins in saliva, is an important modulator of immune response and inflammation, and represents an important defensive element by inducing a broad spectrum of antimicrobial effects against microbial infections. We demonstrated that lactoferrin levels in saliva are decreased in prodromal and dementia stages of AD compared with healthy subjects. That finding seems to be specific to cerebral amyloid-β (Aβ) load as such observation was not observed in healthy elderly controls or those subjects with frontotemporal dementia. In the present study, we analysed salivary lactoferrin levels in a mouse model of AD. We observed robust and early reduction of lactoferrin levels in saliva from 6- and 12-month-old APP/PS1 mice. Because saliva is secreted by salivary glands, we presume that deregulation in salivary glands resulting in reduced salivary lactoferrin levels may occur in AD. To test this hypothesis, we collected submandibular glands from APP/PS1 mice, as well as submandibular gland tissue from AD patients and we analysed the expression levels of key components of the salivary protein signalling pathway. A significant reduction in M3 receptor levels was found along with decreased acetylcholine (Ach) levels in submandibular glands from APP/PS1 mice. Similarly, a reduction in M3 receptor levels was observed in human submandibular glands from AD patients but in that case, the Ach levels were found increased. Our data suggest that the ACh-mediated M3 signalling pathway is impaired in salivary glands in AD, resulting in salivary gland dysfunction and reduced salivary lactoferrin secretion.

Aged Mice Devoid of the M3 Muscarinic Acetylcholine Receptor Develop Mild Dry Eye Disease

The parasympathetic nervous system is critically involved in the regulation of tear secretion by activating muscarinic acetylcholine receptors. Hence, various animal models targeting parasympathetic signaling have been developed to induce dry eye disease (DED). However, the muscarinic receptor subtype (M1–M5) mediating tear secretion remains to be determined. This study was conducted to test the hypothesis that the M3 receptor subtype regulates tear secretion and to evaluate the ocular surface phenotype of mice with targeted disruption of the M3 receptor (M3R−/−). The experimental techniques included quantification of tear production, fluorescein staining of the ocular surface, environmental scanning electron microscopy, assessment of proliferating cells in the corneal epithelium and of goblet cells in the conjunctiva, quantification of mRNA for inflammatory cytokines and prooxidant redox enzymes and quantification of reactive oxygen species. Tear volume was reduced in M3R−/− mice compared to age-matched controls at the age of 3 months and 15 months, respectively. This was associated with mild corneal epitheliopathy in the 15-month-old but not in the 3-month-old M3R−/− mice. M3R−/− mice at the age of 15 months also displayed changes in corneal epithelial cell texture, reduced conjunctival goblet cell density, oxidative stress and elevated mRNA expression levels for inflammatory cytokines and prooxidant redox enzymes. The findings suggest that the M3 receptor plays a pivotal role in tear production and its absence leads to ocular surface changes typical for DED at advanced age.

Association between the glyco-metabolic adverse effects of antipsychotic drugs and their chemical and pharmacological profile: a network meta-analysis and regression

Background Glyco-metabolic deteriorations are the most limiting adverse reactions to antipsychotics in the long term. They have been incompletely investigated and the properties of antipsychotics that determine their magnitude are not clarified. To rank antipsychotics by the magnitude of glyco-metabolic alterations and to associate it to their pharmacological and chemical properties, we conducted a network meta-analysis. Methods We searched PubMed, Embase, and Psycinfo on 10 September 2020. We selected studies containing the endpoint-baseline difference or the distinct values of at least one outcome among glucose, HbA1c, insulin, HOMA-IR, triglycerides, total/HDL/LDL cholesterols. Of 2094 articles, 46 were included in network meta-analysis. Study quality was assessed by the RoB 2 and ROBINS-I tools. Mean differences (MD) were obtained by random-effects network meta-analysis; relations between MD and antipsychotic properties were analyzed by linear regressions. Antipsychotic properties investigated were acidic and basic pKa, polar surface area, polarizability, and occupancies of D2, H1, M1, M3, α1A, α2A, 5-HT1A, 5-HT2A, 5-HT2C receptors. Results We meta-analyzed 46 studies (11 464 patients); on average, studies lasted 15.47 weeks, patients had between 17.68 and 61.06 years of mean age and 61.64% were males. Olanzapine and clozapine associated with greater deteriorations, aripiprazole and ziprasidone with smaller deteriorations. Higher polarizability and 5-HT1A receptor occupancy were associated with smaller deteriorations, H1, M1, and M3 receptor occupancies with larger deteriorations. Conclusions Drug rankings may guide antipsychotic switching toward metabolically safer drugs. Mechanistic insights may suggest improvements for combination therapies and drug development. More data are required regarding newer antipsychotics.

Dissecting Gq/11-Mediated Plasma Membrane Translocation of Sphingosine Kinase-1

Diverse extracellular signals induce plasma membrane translocation of sphingosine kinase-1 (SphK1), thereby enabling inside-out signaling of sphingosine-1-phosphate. We have shown before that Gq-coupled receptors and constitutively active Gαq/11 specifically induced a rapid and long-lasting SphK1 translocation, independently of canonical Gq/phospholipase C (PLC) signaling. Here, we further characterized Gq/11 regulation of SphK1. SphK1 translocation by the M3 receptor in HEK-293 cells was delayed by expression of catalytically inactive G-protein-coupled receptor kinase-2, p63Rho guanine nucleotide exchange factor (p63RhoGEF), and catalytically inactive PLCβ3, but accelerated by wild-type PLCβ3 and the PLCδ PH domain. Both wild-type SphK1 and catalytically inactive SphK1-G82D reduced M3 receptor-stimulated inositol phosphate production, suggesting competition at Gαq. Embryonic fibroblasts from Gαq/11 double-deficient mice were used to show that amino acids W263 and T257 of Gαq, which interact directly with PLCβ3 and p63RhoGEF, were important for bradykinin B2 receptor-induced SphK1 translocation. Finally, an AIXXPL motif was identified in vertebrate SphK1 (positions 100–105 in human SphK1a), which resembles the Gαq binding motif, ALXXPI, in PLCβ and p63RhoGEF. After M3 receptor stimulation, SphK1-A100E-I101E and SphK1-P104A-L105A translocated in only 25% and 56% of cells, respectively, and translocation efficiency was significantly reduced. The data suggest that both the AIXXPL motif and currently unknown consequences of PLCβ/PLCδ(PH) expression are important for regulation of SphK1 by Gq/11.