Genetic differences in the tail-suspension test and its relationship to imipramine response among 11 inbred strains of mice.
BACKGROUND
The tail suspension test (TST) is a simple screening test for the behavioral effects of antidepressants in rodents. This experiment investigated the interindividual differences in responses to stressful situations measured by duration of immobility in the TST and the effects of imipramine (30 mg/kg intraperitoneally) in reducing immobility among 11 inbred strains of mice. The 11 inbred strains were 129S6/SvEvTac, A/J, AKR/J, Balb/cJ, C3H/HeJ, C57BL/6J, DBA/2J, FVB/NJ, NMRI, SencarA/PtJ, and SWR/J.


METHODS
All mice underwent two trials of TST: 1) spontaneous, basal TST and 2) imipramine or saline TST. The duration of immobility was the trait measured during a 6-min test.


RESULTS
In the four strains tested, female mice had longer duration of immobility than male mice in basal TST duration of immobility. For male mice (n = 11 strains), significant strain differences in immobility duration were found for both basal TST and imipramine response TST, with heritability estimates of .31 and .60, respectively. Immobility duration for the DBA/2J, FVB/NJ, and NMRI strains were significantly reduced by imipramine, relative to saline. Surprisingly, this reduction of immobility by imipramine was independent of the basal immobility.


CONCLUSIONS
These results suggest that the responses on basal TST and the imipramine-mediated responses on TST are mediated by separate genetic pathways.
Liu
X
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Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9070, USA.
Gershenfeld
H K
HK
D018759:Adrenergic Uptake Inhibitors / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D000929:Antidepressive Agents, Tricyclic / Q000494:pharmacology*; D001522:Behavior, Animal / Q000187:drug effects*; D005260:Female; D020022:Genetic Predisposition to Disease; D019417:Hindlimb Suspension; D007099:Imipramine / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains / Q000235:genetics* / Q000502:physiology / Q000523:psychology; D012737:Sex Factors
D018759:Adrenergic Uptake Inhibitors; D000929:Antidepressive Agents, Tricyclic; D007099:Imipramine