Effects of long-term administration of melatonin and a putative antagonist on the ageing rat

Neuroreport. 1995 Mar 27;6(5):785-8. doi: 10.1097/00001756-199503270-00020.

Abstract

Adult rats were treated with either melatonin, the putative melatonin antagonist N-(2,4 dinitrophenyl)-5-methoxytryptamine (ML-23), their combination, or a vehicle for 16 months via the drinking water. The survival rates, serum testosterone and densities of 125I-melatonin binding sites in the medulla-pons and hypothalamus of the animals at the age of 27-29 months were significantly higher in the melatonin than vehicle-treated group. Surprisingly, ML-23 without or with melatonin, also prolonged the life-span of the aged animals. ML-23 treatment greatly increased 125I-melatonin binding in the medulla-pons whereas this increase was prevented by melatonin supplementation. Thus melatonin can attenuate age-related decrease in survival rates, testosterone and brain 125I-melatonin binding sites, while chronic blockade by the putative antagonist also elicits melatonin-mimetic responses, perhaps by effecting supersensitivity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 5-Methoxytryptamine / analogs & derivatives*
  • 5-Methoxytryptamine / pharmacology
  • Aging / metabolism*
  • Animals
  • Body Weight / physiology
  • Hypothalamus / drug effects*
  • Hypothalamus / metabolism
  • Iodine Radioisotopes
  • Male
  • Medulla Oblongata / drug effects*
  • Medulla Oblongata / metabolism
  • Melatonin / antagonists & inhibitors
  • Melatonin / pharmacology*
  • Pons / drug effects*
  • Pons / metabolism
  • Random Allocation
  • Rats
  • Receptors, Cell Surface / drug effects
  • Receptors, Cell Surface / metabolism
  • Receptors, Melatonin
  • Survival Rate
  • Testosterone / blood
  • Time Factors

Substances

  • Iodine Radioisotopes
  • Receptors, Cell Surface
  • Receptors, Melatonin
  • ML 23
  • 5-Methoxytryptamine
  • Testosterone
  • Melatonin