Effects of physical training on functional activity of 5-HT1B receptors in rat central nervous system: role of 5-HT-moduline

Naunyn Schmiedebergs Arch Pharmacol. 2000 Jun;361(6):600-4. doi: 10.1007/s002100000242.

Abstract

The effect of physical exercise was examined on the sensitivity of 5-HT1B receptors and on 5-HT-moduline tissue concentration in the central nervous system of rats. Rats were trained for 7 consecutive weeks to run on a treadmill. Three groups of animals were selected: group 1, sedentary rats (controls); group 2, animals running for 1 h at 18 m/min for 5 days per week (moderate training) and group 3, animals running for 2 h, at 30 m/min on a 7% grade for 5 days per week (intensive training). The animals were sacrificed 24 h after the last running. Rat brains were dissected out to obtain hippocampus and substantia nigra and kept at -80 degrees C until use. 5-HT1B receptor activity was determined by studying [35S]GTPgammaS binding in a substantia nigra membrane preparation from individual animals, after stimulation by a selective 5-HT1B receptor agonist (CP 93,129). 5-HT-moduline tissue content in hippocampus from individual animals was determined by ELISA using a polyclonal anti-5-HT-moduline antibody. In moderately trained animals (n=5), the CP 93,129-stimulated [35S]GTPgammaS binding curve was shifted to the right compared with controls (n=6), whereas the binding was totally suppressed in intensely trained animals (n=5). In parallel, 5-HT-moduline tissue concentration in the hippocampus was slightly increased in moderately trained animals (117.3 +/- 8.9%) (n=5), whereas it was significantly increased in intensely trained animals (182.6 +/- 29.5%) (n=5) compared to controls (100 +/- 6.11%) (n=6). These results show that 5-HT1B receptors are slightly desensitized in moderately trained animals and totally desensitized in intensely trained animals; moreover, they suggest that the observed desensitization is related to an increase of 5-HT-moduline tissue content; this mechanism may play a role in various pathophysiological conditions.

MeSH terms

  • Animals
  • Guanosine 5'-O-(3-Thiotriphosphate) / metabolism
  • Hippocampus / metabolism*
  • Male
  • Neuropeptides / metabolism*
  • Oligopeptides / metabolism*
  • Physical Conditioning, Animal
  • Physical Exertion*
  • Pyridines / pharmacology
  • Pyrroles / pharmacology
  • Radioligand Assay
  • Random Allocation
  • Rats
  • Rats, Wistar
  • Receptor, Serotonin, 5-HT1B
  • Receptors, Serotonin / metabolism*
  • Serotonin Receptor Agonists / pharmacology
  • Substantia Nigra / metabolism*

Substances

  • 5-HT-moduline
  • Neuropeptides
  • Oligopeptides
  • Pyridines
  • Pyrroles
  • Receptor, Serotonin, 5-HT1B
  • Receptors, Serotonin
  • Serotonin Receptor Agonists
  • 3-(1,2,5,6-tetrahydropyrid-4-yl)pyrrolo(3,2-b)pyrid-5-one
  • Guanosine 5'-O-(3-Thiotriphosphate)