Treatment of bladder dysfunction with solifenacin: is there a risk of dementia or cognitive impairment?

The use of bladder antimuscarinics is very common in the elderly. However, recent population-based studies that assessed the use of anticholinergics or bladder antimuscarinics showed an increased risk of dementia when these drugs were used for a prolonged period. Several of these population-based studies included patients who used solifenacin, which is a bladder antimuscarinic released in 2005 with the prospect of being a more selective antimuscarinic for M3 receptors (M3R), which could make it a safer drug when trying to avoid unwanted effects of older bladder antimuscarinics such as oxybutynin, especially with regard to changes in cognition. Since the various bladder antimuscarinics have distinct pharmacological characteristics, such as in the ability to penetrate the blood-brain barrier, in selectivity for muscarinic receptors, and in brain efflux mechanisms, their effects on the central nervous system (CNS) may vary. Solifenacin was the drug selected in this review, which aims to describe the results of several articles published in recent years reporting the effects of solifenacin on cognition or the risk of dementia development. Although preclinical studies show that solifenacin can also act on brain M1 receptors (M1R), short-term clinical studies have shown it to be safe for cognition. However, there are no long-term randomized studies that prove the safety of this drug for the CNS. Thus, until the safety of solifenacin has been established by long-term studies, it seems advisable to avoid prolonged use of this drug in elderly patients.

Rapid and long-lasting antidepressant-like effects of ketamine and their relationship with the expression of brain enzymes, BDNF, and astrocytes

Ketamine (KET) is an N-methyl-D-aspartate (NMDA) antagonist with rapid and long-lasting antidepressant effects, but how the drug shows its sustained effects is still a matter of controversy. The objectives were to evaluate the mechanisms for KET rapid (30 min) and long-lasting (15 and 30 days after) antidepressant effects in mice. A single dose of KET (2, 5, or 10 mg/kg, po) was administered to male Swiss mice and the forced swim test (FST) was performed 30 min, 15, or 30 days later. Imipramine (IMI, 30 mg/kg, ip), a tricyclic antidepressant drug, was used as reference. The mice were euthanized, separated into two time-point groups (D1, first day after KET injection; D30, 30 days later), and brain sections were processed for glycogen synthase kinase-3 (GSK-3), histone deacetylase (HDAC), brain-derived neurotrophic factor (BDNF), and glial fibrillary acidic protein (GFAP) immunohistochemical assays. KET (5 and 10 mg/kg) presented rapid and long-lasting antidepressant-like effects. As expected, the immunoreactivities for brain GSK-3 and HDAC decreased compared to control groups in all areas (striatum, DG, CA1, CA3, and mainly pre-frontal cortex, PFC) after KET injection. Increases in BDNF immunostaining were demonstrated in the PFC, DG, CA1, and CA3 areas at D1 and D30 time-points. GFAP immunoreactivity was also increased in the PFC and striatum at both time-points. In conclusion, KET changed brain BDNF and GFAP expressions 30 days after a single administration. Although neuroplasticity could be involved in the observed effects of KET, more studies are needed to explain the mechanisms for the drug's sustained antidepressant-like effects.

Cocos nucifera (L.) (Arecaceae): A phytochemical and pharmacological review

Cocos nucifera (L.) (Arecaceae) is commonly called the “coconut tree” and is the most naturally widespread fruit plant on Earth. Throughout history, humans have used medicinal plants therapeutically, and minerals, plants, and animals have traditionally been the main sources of drugs. The constituents of C. nucifera have some biological effects, such as antihelminthic, anti-inflammatory, antinociceptive, antioxidant, antifungal, antimicrobial, and antitumor activities. Our objective in the present study was to review the phytochemical profile, pharmacological activities, and toxicology of C. nucifera to guide future preclinical and clinical studies using this plant. This systematic review consisted of searches performed using scientific databases such as Scopus, Science Direct, PubMed, SciVerse, and Scientific Electronic Library Online. Some uses of the plant were partially confirmed by previous studies demonstrating analgesic, antiarthritic, antibacterial, antipyretic, antihelminthic, antidiarrheal, and hypoglycemic activities. In addition, other properties such as antihypertensive, anti-inflammatory, antimicrobial, antioxidant, cardioprotective, antiseizure, cytotoxicity, hepatoprotective, vasodilation, nephroprotective, and anti-osteoporosis effects were also reported. Because each part of C. nucifera has different constituents, the pharmacological effects of the plant vary according to the part of the plant evaluated.