Long-term serotonin reinnervation of the suprachiasmatic nucleus after 5,7-dihydroxytryptamine axotomy in the adult rat.
We present here immunohistochemical evidence that serotonin (5-HT) reinnervation in the suprachiasmatic nucleus (SCN) of adult rats, after intraventricular administration of 5,7-dihydroxytryptamine, is more extensive than formerly believed. The first fibers appeared at 4 months and developed until more than 7 months. However, comparison with age-matched controls showed that, even 24 months post-lesion, the density of 5-HT innervation remained abnormally low. At the electron microscopic level, many synaptic contacts were found to have been re-established. The cellular mechanisms possibly responsible for incomplete 5-HT reinnervation in the SCN are discussed.
Bosler
O
O
Laboratoire de Neurobiologie, CNRS, Marseille, France.
Vuillon-Cacciuttolo
G
G
Saïdi
H
H
D015116:5,7-Dihydroxytryptamine / Q000008:administration & dosage / Q000633:toxicity*; D000818:Animals; D001369:Axons / Q000502:physiology / Q000648:ultrastructure; D003714:Denervation; D007276:Injections, Intraventricular; D008297:Male; D009416:Nerve Regeneration; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000502:physiology*; D013493:Suprachiasmatic Nucleus / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure
D015116:5,7-Dihydroxytryptamine; D012701:Serotonin