UNIGE document Scientific Article
previous document  unige:10466  next document
add to browser collection
Title

Role of neuronal nicotinic receptors in the transmission and processing of information in neurons of the central nervous system

Authors
Published in Pharmacology Biochemistry and Behavior. 2001, vol. 70, no. 4, p. 457-466
Abstract The properties of nicotinic acetylcholine receptors (nAChRs) were studied following exogenous expression in a host system or using whole-cell recordings in brain slices, autoradiography and immunohistochemistry. When expressed in HEK-293 cells, alpha 4 beta 2 nAChRs displayed both a high and a low affinity component. The ratio of these two states was modified by chronic nicotine exposure, resulting in an enhanced sensitivity and a marked reduction in desensitization. Mutations in the gene coding for the alpha 4 subunit are responsible for a particular form of nocturnal epilepsy. When expressed in Xenopus oocytes, alpha 4 beta 2 nAChRs containing these mutations displayed distinct alterations in agonist affinity, desensitization and calcium permeability. Magnocellular endocrine neurons in the supraoptic (SO) nucleus of the hypothalamus were found to express functional alpha 7-containing nAChRs, which could play a role in regulating neurohypophysial peptide secretion. Facial (VII), hypoglossal (XII) and vagal (X) motoneurons of young rats responded to ACh by a fast inward current. The nAChRs present in VII and XII nuclei were of the non-alpha 7-containing type, whereas those present in the X nucleus contained the alpha 7 subunit. In Bcl-2 transgenic mice, facial nerve axotomy caused nAChRs downregulation by interfering negatively with the expression of the alpha 4 subunit. Binding sites corresponding to alpha 7-containing nAChRs were also detected in spinal motor nuclei and axotomy provoked a reduction of the binding. Together, these data indicate that long-term exposure to nicotine can promote neuroadaptive changes in nAChRs and that genetic alterations of neuronal nAChRs can result in transmissible neurological diseases. They also suggest that these receptors probably play a role in the central regulation of autonomic functions, as well as in motor control.
Keywords AnimalsCentral Nervous System/drug effects/ physiologyHumansNeurons/drug effects/ physiologyNicotinic Agonists/metabolism/pharmacologyNicotinic Antagonists/metabolism/pharmacologyReceptors, Nicotinic/genetics/ physiology
Stable URL http://archive-ouverte.unige.ch/unige:10466
Full text
Identifiers
PMID: 11796145
Structures
125 hits and 0 download since 2010-08-06
Update
Export document
Format :
Citation style :