title: Metabotropic glutamate receptor mGluR5 is not involved in the early hemodynamic response.
abstract: Activation of astrocytic metabotropic glutamate receptor 5 (mGluR5) is postulated to elicit calcium transients, triggering a chain of events that ultimately regulates cerebral blood flow by changing the tone of smooth muscle cells of nearby arterioles. Using concurrent in vivo optical imaging and determination of receptor occupancy with (11)C-ABP688, we report here that blocking ∼80% of mGluR5 in vivo does not affect transient hemodynamic responses on brief whisker stimulations while transiently reducing neuronal activity as measured by voltage-sensitive dye imaging. Our results show that mechanisms other than activation of mGluR5 are required to trigger the initial hemodynamic response in normal physiological conditions.
authors: Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland.
authors: Novella
authors: N
authors: Calcinaghi
authors: Renaud
authors: R
authors: Jolivet
authors: Matthias T
authors: MT
authors: Wyss
authors: Simon M
authors: SM
authors: Ametamey
authors: Fabrizio
authors: F
authors: Gasparini
authors: Alfred
authors: A
authors: Buck
authors: Bruno
authors: B
authors: Weber
mesh_terms: D000818:Animals; D002525:Cerebellar Cortex / Q000098:blood supply* / Q000166:cytology / Q000378:metabolism; D006439:Hemodynamics; D008297:Male; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D064529:Receptor, Metabotropic Glutamate 5; D018094:Receptors, Metabotropic Glutamate / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: C578937:Grm5 protein, rat; D064529:Receptor, Metabotropic Glutamate 5; D018094:Receptors, Metabotropic Glutamate