title: Distribution of the metabotropic glutamate receptor subtype mGluR5 in rat midbrain periaqueductal grey and relationship with ascending spinofugal afferents.
abstract: The periaqueductal grey matter (PAG) is known to adjust somatic and neurovegetative elements of the defence behaviour. We have used specific polyclonal antibodies to examine the distribution of the metabotropic glutamate receptor subtype 5 (mGluR5) in this region. Immunolabelling for mGluR5 displayed a net preference for dorsolateral areas at rostral and intermediate levels. Electronmicroscopic examination revealed that mGluR5 is expressed in neuronal perikarya and in dendrites receiving synaptic contacts of Gray I type. To investigate the possible relevance of mGluR5 to integration of somatosensory information, spinoannular (SA) neurones were peroxidase-labelled and their relationship with mGluR5-expressing PAG neurones was examined at the ultrastructural level. A number of synaptic terminals of the SA pathway established synaptic contact of asymmetric type onto mGluR5-immunoreactive dendrites. It is suggested that mGluR5 might be involved in the temporal integration of somatosensory inputs to the PAG.
authors.affiliation: Neurosciences Department, Faculty of Medicine and Dentistry Basque Country University, Bilbao, Spain. bw9@ix.urz.uni-heidelberg.de
authors.forename: J J
authors.initials: JJ
authors.lastname: Azkue
authors.forename: T
authors.initials: T
authors.lastname: Knöpfel
authors.forename: R
authors.initials: R
authors.lastname: Kuhn
authors.forename: J M
authors.initials: JM
authors.lastname: Mateos
authors.forename: P
authors.initials: P
authors.lastname: Grandes
mesh_terms: D000818:Animals; D007150:Immunohistochemistry; D008297:Male; D008636:Mesencephalon / Q000166:cytology / Q000378:metabolism*; D008854:Microscopy, Electron; D009475:Neurons, Afferent / Q000502:physiology*; D010487:Periaqueductal Gray / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D064529:Receptor, Metabotropic Glutamate 5; D018094:Receptors, Metabotropic Glutamate / Q000378:metabolism*; D013116:Spinal Cord / Q000166:cytology / Q000502:physiology*; D014018:Tissue Distribution
chemical_list: C578937:Grm5 protein, rat; D064529:Receptor, Metabotropic Glutamate 5; D018094:Receptors, Metabotropic Glutamate