Antidepressant-like behavioral effects of IGF-I produced by enhanced serotonin transmission.

Previous research has suggested that mobilization of neurotrophic factors, such as insulin-like growth factor I (IGF-I), can be involved in the effects of antidepressant treatments. The current experiments showed that IGF-I leads to antidepressant-like effects in the modified rat forced swim test when tested 3 days, but not 1 day, after i.c.

Differential regulation of central BDNF protein levels by antidepressant and non-antidepressant drug treatments.

Antidepressant treatments have been proposed to produce their therapeutic effects, in part, through increasing neurotrophin levels in the brain. The current experiments investigated the effects of acute and chronic treatment with different pharmacologic and somatic antidepressant treatments on protein levels of BDNF in several brain regions associated with depression in the rat. Repeated applications (10 days) of electroconvulsive shock (ECS), but not a single treatment (1 day), produced 40-100% increases of BDNF protein in the hippocampus, frontal cortex, amygdala, and brainstem.

Social competition in rats: cell proliferation and behavior.

Behavioral and physiological changes were studied following prolonged exposure to social competition in pairs of non-food-deprived rats competing daily for a limited supply of graham cracker crumbs. Stable dominant-subordinate relationships developed in most pairs, as measured by feeding time, which were maintained over a 5-6-week study period. In other behavioral tests, subordinates demonstrated a decreased latency to immobility in the forced swim test compared with dominants, but no difference in locomotor activity.

Delta opioid receptor ligands modulate anxiety-like behaviors in the rat.

The role of the delta opioid receptor in regulating anxiety-like behavior in male Sprague-Dawley rats was examined. Using an elevated plus maze, the effects of the selective delta opioid receptor antagonist naltrindole (1 or 5 mg kg(-1)) and agonist SNC80 (1, 5 or 20 mg kg(-1)) on anxiety-like behavior were measured. Anxiety was also measured following administration of diazepam (3 mg kg(-1)) and amphetamine (1 mg kg(-1)) and compared to the effects of SNC80.

Central administration of IGF-I and BDNF leads to long-lasting antidepressant-like effects.

Drug development research has identified neurotrophic factors as a downstream target of chronic antidepressant treatments. In order to study their antidepressant-like effects, two neurotrophic factors, brain-derived neurotrophic factor and insulin-like growth factor I, were examined in the rat modified forced swimming test after a single icv administration. Both neurotrophins produced antidepressant-like behavioral effects in the modified rat forced swimming test, reducing immobility and increasing swimming.