The ontogeny of spinal cord monoamines and the post-decapitation reflex.

Abstract

The ontogeny of the post-decapitation reflex (PDR) was examined in neonatal systemic 6-hydroxydopamine (6-OHDA) treated rats. The PDR was absent in the youngest (5 day) and oldest (60 day) 6-OHDA treated rats but present with attenuated characteristics at around 15 and 20 days. The reappearance of the PDR in these rats closely paralleled age-related fluctuations in spinal cord noradrenaline (NE) which increased until 15 days, then precipitously declined, but did not correlate with spinal dopamine (DA) or serotonin (5-HT). The failure of the alpha noradrenergic blocking agents chlorpromazine, phenoxybenzamine, prazosin, or yohimbine to eliminate the vestigial PDR in the 15-20-day-old, 6-OHDA-treated rats indicates that this is probably not mediated by remaining, undamaged spinal NE neurons at this age. Neither is it likely to be mediated by spinal 5-HT neurons since inhibition of 5-HT synthesis had no effect upon the PDR latency in normal or neonatal 6-OHDA-treated, 17-day-old rats. In contrast to NE levels which increased with age in normal rats, spinal cord 5-HT and DA levels at least as high at 5 days of age as at adulthood.

• Authors: B A Pappas, R Ings
• Journal: Pharmacology, biochemistry, and behavior (Pharmacol Biochem Behav) Vol. 16 Issue 4 Pg. 615-9 (Apr 1982) ISSN: 0091-3057 [Print] United States
• PMID: 6122217 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Hydroxydopamines
• Neurotransmitter Agents
• Serotonin
• Oxidopamine
• Dopamine
• Norepinephrine

Topics

• Aging
• Animals
• Dopamine (physiology)
• Female
• Hydroxydopamines (pharmacology)
• Locus Coeruleus (physiology)
• Male
• Muscle Contraction (drug effects)
• Neural Inhibition (drug effects)
• Neurotransmitter Agents (physiology)
• Norepinephrine (physiology)
• Oxidopamine
• Rats
• Rats, Inbred Strains
• Reflex (physiology)
• Serotonin (physiology)
• Spinal Cord (drug effects, physiology)