Interferon and the central nervous system

Interferons (IFNs) were discovered as natural antiviral substances produced during viral infection and were initially characterized for their ability to "interfere" with viral replication, slow cell proliferation, and profound alteration of immunity. The IFNs are synthesized and secreted by monocytes, macrophages, T-lymphocytes, neurons, and glia cells. The different IFNs are classified into three classes: alpha, beta, and gamma. alpha-IFN produced in the brain exerts direct effects on the brain and endocrine system by activating the neurosecretory hypothalamic neurons and regulates the hypothalamic-pituitary-adrenocortical axis. IFNs modulate neurophysiological activities of many brain region involving in pain, temperature, and food intake regulation. alpha-IFN administration activates the sympathetic nerves innervating components of the immune system. IFNs may serve as regulatory mediators between the central nervous system, the immune system, and endocrine system. IFN is used as immunologic therapy to treat various hematologic malignancies and infectious ailments and autoimmune diseases.     

Plants and the central nervous system

This review article draws the attention to the many species of plants possessing activity on the central nervous system (CNS). In fact, they cover the whole spectrum of central activity such as psychoanaleptic, psycholeptic and psychodysleptic effects, and several of these plants are currently used in therapeutics to treat human ailments.Among the psychoanaleptic (stimulant) plants, those utilized by human beings to reduce body weight [Ephedra spp. (Ma Huang), Paullinia spp. (guaraná), Catha edulis Forssk. (khat)] and plants used to improve general health conditions (plant adaptogens) were scrutinized.Many species of hallucinogenic (psychodysleptic) plants are used by humans throughout the world to achieve states of mind distortions; among those, a few have been used for therapeutic purposes, such as Cannabis sativa L., Tabernanthe iboga Baill. and the mixture of Psychotria viridis Ruiz and Pav. and Banisteriopsis caapi (Spruce ex Griseb.) C.V. Morton. Plants showing central psycholeptic activities, such as analgesic or anxiolytic actions (Passiflora incarnata L., Valeriana spp. and Piper methysticum G. Forst.), were also analysed.Finally, the use of crude or semipurified extracts of such plants instead of the active substances seemingly responsible for their therapeutic effect is discussed.     

Effects of mellitin on the central nervous system.

Mellitin, the main toxic component of bee venom was injected in cats intravenously and through the carotid or vertebral arteries. The main effect on the electrocorticogram was depression. This may be due to changes in blood properties (hemolysis, hemoconcentration, hyperkalemia) and to hypotension.     

Effects of polyamines on the central nervous system.

Effects of polyamines on the central nervous system were studied in mice. Intraperitoneal administration of Spermidine (SPD) and Spermine (SPM) decreased spontaneous motor activity as measured by either the photo-cell counters method or the open-field test and lowered rectal temperature. A significant prolongation of sleeping time after pentobarbital was confirmed in small doses of SPD and SPM which had slight influence on spontaneous motor activity. The time to convulsion and death induced by strychnine was elongated by SPD and SPM. SPM in small doses inhibited writhing responses induced by 0.7% acetic acid. In addition, methamphetamine-induced hyperactivity and conditioned avoidance response were blocked by SPM in doses which decreased spontaneous motor activity. In all experiments, SPM appeared to have a powerful pharmacological activity compared with SPD. LD50 for SPD and SPM was 620 (500-769) mg/kg i.p. and 310 (200-480) mg/kg i.p., respectively.     

Vitamin D and the central nervous system

Vitamin D is formed in human epithelial cells via photochemical synthesis and is also acquired from dietary sources. The so-called classical effect of this vitamin involves the regulation of calcium homeostasis and bone metabolism. Apart from this, non-classical effects of vitamin D have recently gained renewed attention. One important yet little known of the numerous functions of vitamin D is the regulation of nervous system development and function. The neuroprotective effect of vitamin D is associated with its influence on neurotrophin production and release, neuromediator synthesis, intracellular calcium homeostasis, and prevention of oxidative damage to nervous tissue. Clinical studies suggest that vitamin D deficiency may lead to an increased risk of disease of the central nervous system (CNS), particularly schizophrenia and multiple sclerosis. Adequate intake of vitamin D during pregnancy and the neonatal period seems to be crucial in terms of prevention of these diseases.