Endocannabinoid Receptors in the CNS: Potential Drug Targets for the Prevention and Treatment of Neurologic and Psychiatric Disorders

The endocannabinoid system participates in the regulation of CNS homeostasis and functions, including neurotransmission, cell signaling, inflammation and oxidative stress, as well as neuronal and glial cell proliferation, differentiation, migration and survival. Endocannabinoids are produced by multiple cell types within the CNS and their main receptors, CB₁ and CB₂, are expressed in both neurons and glia. Signaling through these receptors is implicated in the modulation of neuronal and glial alterations in neuroinflammatory, neurodegenerative and psychiatric conditions, including Alzheimer’s, Parkinson’s and Huntington’s disease, multiple sclerosis, amyotrophic lateral sclerosis, stroke, epilepsy, anxiety and depression. The therapeutic potential of endocannabinoid receptors in neurological disease has been hindered by unwelcome side effects of current drugs used to target them; however, due to their extensive expression within the CNS and their involvement in physiological and pathological process in nervous tissue, they are attractive targets for drug development. The present review highlights the potential applications of the endocannabinoid system for the prevention and treatment of neurologic and psychiatric disorders.

The impact of nutritive and non-nutritive sweeteners on the central nervous system: preliminary study

BACKGROUND

Human consumption of food and beverages containing added nutritive or non-nutritive sweeteners has increased worldwide.

OBJECTIVE

The present study evaluated the possible impact of frequent sweetener consumption on human CNS activity and functions through neuropsychological testing and EEG/qEEG analysis.

METHODS

A sample of 23 women and 16 men, aged 18-35, with a body mass index between 18 and 24.9 kg/m² was evaluated. Participants underwent a 1-week washout period in which food with added sugars or sweeteners was restricted from their diet. Initial assessment of cognitive functions was performed with a validated neuropsychological test and EEG/qEEG analysis, prior to supplementation. Sucrose, sucralose, or steviol glycosides, in commercially available presentations, were randomly assigned to three experimental groups of 13 participants each. Sweeteners were supplemented in fixed amounts, daily, for six weeks. After supplementation, neurological tests were repeated and the initial and final results were compared.

RESULTS

The results show no significant changes between final and initial measures in the steviol glycosides group. However, a significant decrease in encoding memory was found in the sucrose group in the final evaluation. Strikingly, the sucralose group showed a significant decrease in overall memory, encoding memory, and executive functions after supplementation. Furthermore, qEEG analysis showed an increase in theta wave absolute and relative power at the final evaluation in the same group.

CONCLUSION

These data show that frequent consumption of specific sweeteners is accompanied by measurable changes in EEG/qEEG activity and neuropsychological test performance in humans.

Changes in nutrient and calorie intake, adipose mass, triglycerides and TNF-α concentrations after non-caloric sweetener intake: A pilot study

Establishing the safety of non-caloric sweetener consumption in humans is a difficult task, since many contradictory results have been reported. The objective of this study was to compare the effect of frequent intake of sucrose, sucralose or steviol glycosides, on selected anthropometric, biochemical and immunological parameters in healthy, young adults. 38 individuals with normal body mass index were recruited and randomly divided into three experimental groups. After a washout week (where food with added sweeteners was restricted), each group was supplemented with sucrose (8 × 5 g packets/day), sucralose or steviol glycosides (4 × 1 g packets/day each) for 6 weeks. Selected variables were measured before and after treatment in each group and differences within and among groups were assessed. Our results showed that, compared to baseline, there was a modest but significant increase in weight (p = 0.0293) in the sucralose group, while the steviol glycosides group reduced their fat mass (p = 0.0390). No differences were observed in glycaemia; however, there was a significant increase in serum triglycerides (77.8-110.8 mg/dL) and cholesterol (162.0-172.3 mg/dL) in the sucrose group, whereas the steviol glycosides group presented lower triglycerides (104.7-92.8 mg/dL) and TNF-α concentrations (51.1-47.5 pg/mL). Comparison among groups showed differences in serum triglycerides (p = 0.0226), TNF-α (p = 0.0460) and IL-β (p = 0.0008). Our results suggest that, even in a short time span, frequent intake of steviol glycosides may have positive effects on metabolic parameters that may be relevant for human health.

Comparative study of the activity and lingering effect of topical antifungals

We present a combined method of culturing pathogenic dermatophytes and yeasts on human stratum corneum. Topical marketed antifungals are applied in vivo, and the stratum corneum is removed by cyanoacrylate skin surface strippings. After inoculation of the test organism, the extent of fungal growth is measured, indicating by comparison with controls the level of inhibitory effect of the antifungal. Other samples of stratum corneum collected at different time intervals after the arrest of antimicrobial treatment are used to evaluate the lingering effect of the drug. The combination of the data gained by these approaches close to the in vivo situation is used to introduce a classification of antifungals.

Dermatopathological aspects of restrictive dermopathy

We present an immunopathological and electronmicroscopic study of the skin of two newborns affected by restrictive dermopathy. Evidence of abnormal maturation was found in the epidermis, cutaneous appendages, dermis, and hypodermis. Our observations confirm two previous descriptions. We emphasize some unreported data concerning the L1 antigen and Factor XIIIa in the skin. The L1 antigen is expressed in the interadnexal epidermis, but not in hair follicles. This is the reverse pattern compared with normal skin. Factor XIIIa is poorly expressed in dermal dendrocytes, which appear rare compared with controls. The multiple defects in maturation found in all cutaneous tissues suggest a qualitative or quantitative aberration in control mechanisms of tissue interactions.

Cutaneous hamartoma with pagetoid cells

We report an unusual cutaneous hamartoma with pagetoid cells characterized by the presence of intraepidermal cells resembling Toker's cells of the nipple. These cells were EMA positive and could be related to the histogenesis of some Paget's disease.

Cutaneous presentation of the cardio-facio-cutaneous syndrome

We present the clinical and histologic features of the cutaneous lesions in a girl with cardio-facio-cutaneous syndrome. Marked tortuosity with hyperkeratosis of the sweat ducts and dystrophy of the hair shafts appear to be the cutaneous hallmarks of this syndrome.

Cutaneous mixed infections in AIDS

We report a new case of mixed infection occurring at the same site of the skin in a human immune deficiency virus-positive patient. Hyperkeratotic and crusted erosions contained fusospirochetal organisms, Cryptococcus neoformans, and another unidentified fungus.

Identification of Taenia solium antigens in cerebrospinal fluid and larval antigens from patients with neurocysticercosis

Two antigens (190 and 230 kDa) of the larvae of Taenia solium were detected in the cerebrospinal fluid (CSF) of 14 of 18 patients in which neurocysticercosis was suspected. Nine of these were confirmed by histopathology. Seven antigens were detected in cyst fluid of T. solium larvae removed from the brains of 6 infected patients. Two of these antigens had the same Mr as the T. solium antigens detected in the CSF. Polyacrylamide gel electrophoresis and electro-immunoblotting analyses were used for the identification and characterization. Antibodies in rabbit anti-larval antiserum and antibodies in sera of infected individuals recognized the same larval antigens in the larval cyst fluids and in the CSF of infected patients.