On the relationship of neuropeptide Y Y1 receptor-immunoreactive neuronal structures to the neuropeptide Y-immunoreactive nerve terminal networks. A double immunolabelling analysis in the rat brain.
Neuropeptide Y is the most abundant peptide in the mammalian central nervous system and exhibits a variety of potent neurobiological functions. In the present study, double immunolabelling histochemistry was performed, using previously characterized antibodies against neuropeptide Y and the neuropeptide Y Y1 receptor subtype, to clarify the cellular distribution of Y1 receptors in the rat brain in relation to the neuropeptide Y-immunoreactive systems. Based on fluorescence and confocal laser microscopy analysis, morphological evidence is presented that the perikaryal and dendritic Y1 receptor-like immunoreactivity demonstrated in discrete regions of the tel-, diencephalon and of the lower brain stem, shown to be cytoplasmic and membrane associated, in many brain regions is not co-distributed with the neuropeptide Y-immunoreactive terminal network. These findings may partly be explained by the existence of volume transmission in Y1 receptor-mediated neuropeptide Y transmission involving short to long distance diffusion and/or convection of neuropeptide Y from its site of release to the neuronal target cells, containing the high-affinity Y1 receptors. Furthermore, neuropeptide Y and Y1 receptor-like immunoreactivities were in no case co-localized in the same nerve cell, suggesting that, in the rat brain, the Y1 receptor subtype may not be a neuropeptide Y autoreceptor.
Department of Neuroscience, Karolinska Institute, Stockholm, Sweden.
L
L
Caberlotto
B
B
Tinner
B
B
Bunnemann
L
L
Agnati
K
K
Fuxe
D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D009411:Nerve Endings / Q000378:metabolism* / Q000648:ultrastructure; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D009478:Neuropeptide Y / Q000378:metabolism*; D010446:Peptide Fragments / Q000737:chemistry / Q000276:immunology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017476:Receptors, Neuropeptide Y / Q000378:metabolism*
D009478:Neuropeptide Y; D010446:Peptide Fragments; D017476:Receptors, Neuropeptide Y; C097212:neuropeptide Y-Y1 receptor