Effects of retinal deafferentation on serotonin receptor types in the superficial grey layer of the superior colliculus of the rat.
The effects of retinal axon terminal degeneration on the serotonin-1A, -1B, -2, nuerokinin-1 and gamma-amionobutyric acid-A high affinity binding sites in the superficial grey layer of the superior colliculus were tested with quantitative autoradiography on rat brain sections. The binding to serotonin-2, neurokinin-1 and gamma-aminobutyric acid-A high affinity receptors was not changed in the deafferented superficial grey layer of the superior colliculus after unilateral enucleation. By contrast, we demonstrate that the previously described 21% decrease in the binding of [3H]serotonin to serotonin-1 receptors observed in the deafferented superficial grey layer of the superior colliculus after enucleation, was not due to a decrease in the affinity of the serotonin-1 receptors for the radioligand, but to a decrease in the number of binding sites. Of the different serotonin-1 receptor subtypes, only the serotonin-1B was lost. This signifies that these receptors are probably located on the optic fibre terminals. Visual cortex lesion caused no apparent regulation of the serotonin-1 binding sites in the superficial grey layer of the superior colliculus. A bilateral enucleation produced a smaller decrease in serotonin-1 receptor density than that observed after unilateral enucleation, suggesting the existence of a compensatory mechanism.
CNRS Laboratoire de Neurobiologie-E6, Marseille, France.
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Boulenguez
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Abdelkefi
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Pinard
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Christolomme
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Segu
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D000818:Animals; D001345:Autoradiography; D003714:Denervation; D015353:Eye Enucleation; D007700:Kinetics; D008297:Male; D009410:Nerve Degeneration / Q000502:physiology; D009475:Neurons, Afferent / Q000502:physiology*; D011869:Radioligand Assay; D051381:Rats; D017207:Rats, Sprague-Dawley; D011963:Receptors, GABA-A / Q000187:drug effects / Q000378:metabolism; D017981:Receptors, Neurotransmitter / Q000187:drug effects / Q000378:metabolism; D011985:Receptors, Serotonin / Q000187:drug effects / Q000378:metabolism*; D018039:Receptors, Tachykinin; D012160:Retina / Q000502:physiology*; D013477:Superior Colliculi / Q000033:anatomy & histology / Q000378:metabolism*; D013569:Synapses / Q000187:drug effects / Q000378:metabolism; D014793:Visual Cortex / Q000502:physiology
D011963:Receptors, GABA-A; D017981:Receptors, Neurotransmitter; D011985:Receptors, Serotonin; D018039:Receptors, Tachykinin; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin