Intermittent and continuous swim stress-induced behavioral depression: sensitivity to norepinephrine- and serotonin-selective antidepressants.

Rationale: Intermittent swim stress (ISS) produces deficits in swim escape learning and increases immobility in the forced swim test (FST). A previous attempt to reverse this immobility with the selective serotonin reuptake inhibitor (SSRI), fluoxetine (FLX), was unsuccessful, but the sensitivity of this immobility to other types of antidepressants is unknown.

Objectives: In experiment 1, we evaluate the ability of the norepinephrine (NE) selective reuptake inhibitor (NSRI), desipramine (DES), to reverse the ISS-induced immobility in the FST compared to confined controls (CC), while in experiment 2, we test the efficacy of either the SSRI or NSRI to reverse the immobility produced by either ISS or continuous swim (CS)/FST.

Primarily nonlinear effects observed in a driven asymmetrical vibrating wire.

The purpose of the work reported here is to further experimentally explore the wide variety of behaviors exhibited by driven vibrating wires, primarily in the nonlinear regime. When the wire is driven near a resonant frequency, it is found that most such behaviors are significantly affected by the splitting of the resonant frequency and by the existence of a "characteristic" axis associated with each split frequency. It is shown that frequency splitting decreases with increasing wire tension and can be altered by twisting.