title: Forced swimming stress does not affect monoamine levels and neurodegeneration in rats.
abstract: OBJECTIVE
  The current study was aimed to investigate the correlations between immobility time in the forced swimming test (FST, a behavioral indicator of stress level) and hippocampal monoamine levels (markers of depression), plasma adrenalin level (a peripheral marker of stress) as well as fluoro-jade C staining (a marker of neurodegeneration).
  
  
  METHODS
  Male Sprague-Dawley rats were subjected to acute, sub-chronic (7 d) or chronic (14 d) FSTs and immobility time was recorded. Levels of noradrenalin, serotonin and dopamine in the hippocampus, and adrenalin level in the plasma were quantified by high-performance liquid chromatography with electrochemical detection. Brain sections from rats after chronic forced swimming or rotenone treatment (3 mg/kg subcutaneously for 4 d) were stained with fluoro-jade C.
  
  
  RESULTS
  The rats subjected to swimming stress (acute, sub-chronic and chronic) showed long immobility times [(214 +/- 5), (220 +/- 4) and (231 +/- 7) s, respectively], indicating that the animals were under stress. However, the rats did not exhibit significant declines in hippocampal monoamine levels, and the plasma adrenalin level was not significantly increased compared to that in unstressed rats. The rats that underwent chronic swimming stress did not manifest fluoro-jade C staining in brain sections, while degenerating neurons were evident after rotenone treatment.
  
  
  CONCLUSIONS
  The immobility time in the FST does not correlate with markers of depression (monoamine levels) and internal stress (adrenalin levels and neurodegeneration), hence this parameter may not be a true indicator of stress level.
authors.affiliation: Pharmacology Section, H.E.J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan. E-mail: ahsanadar@hotmail.com.
authors.forename: Ghulam
authors.initials: G
authors.lastname: Abbas
authors.forename: Sabira
authors.initials: S
authors.lastname: Naqvi
authors.forename: Shahab
authors.initials: S
authors.lastname: Mehmood
authors.forename: Nurul
authors.initials: N
authors.lastname: Kabir
authors.forename: Ahsana
authors.initials: A
authors.lastname: Dar
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D015306:Biogenic Monoamines / Q000378:metabolism*; D003863:Depression / Q000378:metabolism*; D004837:Epinephrine / Q000097:blood; D005452:Fluoresceins; D006624:Hippocampus / Q000378:metabolism / Q000473:pathology*; D046353:Immobility Response, Tonic / Q000502:physiology; D008297:Male; D009410:Nerve Degeneration / Q000378:metabolism / Q000473:pathology; D051381:Rats; D013194:Staining and Labeling; D013315:Stress, Psychological / Q000378:metabolism* / Q000473:pathology; D013550:Swimming; D013997:Time Factors
chemical_list: D015306:Biogenic Monoamines; D005452:Fluoresceins; C534582:fluoro-jade C; D004837:Epinephrine