The effects of serotonin manipulation during the postnatal period on the development of sexually dimorphic and non-dimorphic lumbosacral motor neuron groups in the albino Swiss rat.
Serotonin (5-HT) may act during development as a neurotrophic agent. Evidence suggests that sexually dimorphic regions of the mammalian nervous system (which often possess sexually dimorphic patterns of 5-HT innervation) could provide a model for this aspect of 5-HT action. Albino Swiss rat pups were treated with p-chlorophenyl alanine (pCPA, 200 mg/kg) or 5-hydroxytryptophan (5-HTP, 75 mg/kg) for 14 days after birth. As adults, the number of motor neurons in the sexually dimorphic spinal nucleus of bulbocavernosus (SNB) and dorsolateral nucleus (DLN), together with the non-dimorphic ventromedial nucleus (VM) were analysed. Postnatal treatment with 5-HTP had a general effect of increasing motor neuron numbers in all three groups. However, pCPA treatment had a marked and specific effect on SNB neuron numbers, increasing these in both sexes (+250% in females and +60% in males) compared with control animals. The results suggest that the postnatal innervation of ventral horn motor neurons by 5-HT-containing terminals may affect cell death at this time.
Cowburn
P J
PJ
Department of Anatomy, Glasgow University, UK.
Payne
A P
AP
D000818:Animals; D001921:Brain / Q000166:cytology / Q000187:drug effects / Q000254:growth & development; D002452:Cell Count; D005260:Female; D010134:Fenclonine / Q000494:pharmacology; D008161:Lumbosacral Region; D008297:Male; D009046:Motor Neurons / Q000166:cytology* / Q000187:drug effects; D009130:Muscle, Smooth / Q000294:innervation; D010502:Perineum / Q000294:innervation; D051381:Rats; D012701:Serotonin / Q000502:physiology*; D012727:Sex Characteristics; D013116:Spinal Cord / Q000166:cytology / Q000187:drug effects / Q000254:growth & development*
D012701:Serotonin; D010134:Fenclonine