Aspects on nitric oxide as functions cellular messenger of the central nervous system [Aspectos sobre las funciones del óxido nítrico como mensajero celular en el sistema nervioso central]
Por:
Talavera-Cuevas E., Condes-Lara M., Martínez-Lorenzana G.
Publicada:
1 ene 2003
Resumen:
The discovery of nitric oxide (NO) in the last decade opened a new and important research field that has provided new insights on communication and regulation mechanisms taking place in different cellular populations, including animals and plants. In humans, this molecule participates in the physiology of almost all bodily systems such as cardiovascular, nervous, respiratory, and reproductive tracts. This means that alterations in its synthesis originate various pathological modifications, including hypertension, impotence, vascular complications, diabetes, asthma, and neurodegeneration. In the nervous system, nitric oxide acts as a cellular messenger, and together with carbon monoxide forms the gaseous neurotransmitter family. It is considered an atypical neurotransmitter since it is not stored in synaptic vesicles. Once synthetized it diffuses through the cellular membrane reaching different target molecules within a 40-100 ?m radius, lacking a specific receptor molecule. One of its best known target molecules is guanylate cyclase, which is activated to produce the necessary cyclic GMP to relax blood vessels. Among its properties is that of being a free radical, which means that it has an unpaired electron, making it highly reactive with other molecules such as the radicals superoxide, hemeproteins, thiol and amino groups, as well as oxygen. Thus, NO participates in various signaling mechanisms regulating the activity of several proteins and gene expression. Besides, NO can be released from nervous terminals, axons, and neuronal cell bodies. In all cellular types of animal and plants where NO has been detected, it has been found that its precursor is the aminoacid L-arginine, and its by-product is L-citrulline. The synthesis reaction takes place thanks to a family of isoenzymes known as nitric oxide synthases (NOS). These were named, depending on their isolation and cloning site, as endothelial, neuronal, and inducible. Although these enzymes have similar molecular characteristics, the synthetic activity of each one of them depends on various factors such as the NO amount produced on the tissue of the organ where the enzyme this molecule could be associated with neuroprotection. Understanding of the NO synthetic pathway and the availability of different NO inhibitory or donating molecu
Filiaciones:
Talavera-Cuevas E.:
Instituto de Neurobiología, Campus UNAM-UAQ Juriquilla, Querétaro, Mexico
Instituto de Neurobiología, Depto. Neurbio. Desarrollo y Fisiol., Campus UNAM-Juriquilla, Querétaro, 17001, Mexico
Condes-Lara M.:
Instituto de Neurobiología, Campus UNAM-UAQ Juriquilla, Querétaro, Mexico
Martínez-Lorenzana G.:
Instituto de Neurobiología, Campus UNAM-UAQ Juriquilla, Querétaro, Mexico
|