Paper Information

Title:  NORADRENERGIC SYSTEM INCREASES SPONTANEOUS SYNAPTIC TRANSMISSION IN THE BARREL CORTEX
Type: SPEECH
Author(s): HAGH DOUST YAZDI H.*,STRICKER C.
 
 *DEPT. OF PHYSIOLOGY, QAZVIN UNIVERSITY OF MEDICAL SCIENCES, QAZVIN, IRAN
 
Name of Seminar: IRANIAN CONGRESS OF PHYSIOLOGY AND PHARMACOLOGY
Type of Seminar:  CONGRESS
Sponsor:  PHYSIOLOGY AND PHARMACOLOGY SOCIETY, MASHHAD UNIVERSITY OF MEDICAL SCIENCE
Date:  2007Volume 18
 
 
Abstract: 

Neurons in layer II of Somatosensory cortex show high frequency (33 ± 13 Hz) spontaneous postsynaptic currents which their rates and amplitudes are independent of sodium channels. Most of them represent miniature excitatory postsynaptic currents (mEPSCs) and are largely mediated by glutaminergic AMPA receptors. These currents are important in pathogenesis of Alzheimer's and other neurodegenerative diseases and both ryanodine- and IP3-mediated Ca2+ stores participate in their inductions. To understand factors that control induction of mEPSCs, the neurotransmitter systems are noticed and because cortical neurons receive dense noradrenergic innervations, we examined effects of noradrenergic system. For this, whole cell patch clamp recordings were made on pyramidal neurons of the barrel cortex from brain slices that continuously superfused with artificial cerebrospinal fluid (ACSF) containing tetrodotoxin and picrotoxin. Significant increase in frequency of the mEPSCs was observed after application of noradrenalin. Using specific agonists of the noradrenergic system, it was revealed the effects of noradrenergic system on the mEPSCs are largely mediated by a1 receptor. Regarding other reports that show noradrenergic system suppresses sodium dependent excitatory synaptic transmission, it seems noradrenergic system has dual effects on synaptic transmission, depresses it in active condition while promotes it during resting state.

 
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