Stock differences in the susceptibility of rats to learned helplessness training

The effect of corticotropin-releasing factor on prepulse inhibition is independent of serotonin in Brown Norway and Wistar-Kyoto rats

“…For example, WKY rats exhibit greater anxiety-like behavior in the elevated plus maze, as they spend significantly less time in the open arms of the maze compared to BN rats Ramos et al, 1997). WKY rats are also highly susceptible to learned helplessness while BN rats show a complete lack of susceptibility (Wieland et al, 1986). It would be interesting to examine whether CRF and 5-HT interact to mediate these behaviors in a manner similar to those observed in other rat strains, even though CRF and 5-HT do not interact to mediate PPI in WKY and BN rats.…”

Mother–infant separation leads to hypoactive behavior in adolescent Holtzman rats

“…Different strains of albino rats, such as Harlan SD and HO, share a common origin and likely share a majority of their genes. However, we hypothesized that our MS protocol may lead to hypoactive behavioral effects in HO rats because of their greater susceptibility to show depressive-like behavioral responses to stress in comparison to SD rats in the learned helplessness paradigm (Wieland et al, 1986). These behavioral differences may be related to reported strain differences in regulatory systems, including the reproductive system and the hypothalamic-pituitary-adrenal (HPA) axis (Matthys et al, 1998).…”

Strain Differences in the Behavioral Effects of Antidepressant Drugs in the Rat Forced Swimming Test

“…One inbred rat strain, the Wistar-Kyoto (WKY) rat bred initially from the Wistar rat as the control strain for the spontaneously hypertensive rat or SHR (Okamoto and Aoki 1963), has been proposed as an animal model of depressive behavior (Paré 1989;Paré and Redei 1993;Marti and Armario 1996), because they consistently demonstrate exaggerated behavioral and physiological responses to stress across a variety of situations in comparison to other strains. The WKY strain is one of the most susceptible to developing learned helplessness (Wieland et al 1986;Paré 1994) (Paré 1993;Paré 1996), and demonstrate greater hypo neophagia; that is, the fear of feeding in a novel environment when hungry, than other rat strains (Paré 1994). As expected from this profile, WKY rats readily acquire passive avoidance behaviors, but they demonstrate deficits when emitting active avoidance or anxiety-related behaviors (Paré 1994).…”

“…One inbred rat strain, the Wistar-Kyoto (WKY) rat bred initially from the Wistar rat as the control strain for the spontaneously hypertensive rat or SHR (Okamoto and Aoki 1963), has been proposed as an animal model of depressive behavior (Paré 1989;Paré and Redei 1993;Marti and Armario 1996), because they consistently demonstrate exaggerated behavioral and physiological responses to stress across a variety of situations in comparison to other strains. The WKY strain is one of the most susceptible to developing learned helplessness (Wieland et al 1986;Paré 1994) and demonstrates higher levels of behavioral immobility at baseline in the forced swimming test (FST;Paré 1994;Armario et al 1995), two rodent tests sensitive to antidepressant drugs. Also, WKY rats show greater signs of emotionality and a tendency to freeze in stressful situations (Berger and Starzic 1988), exhibit little exploratory behavior in the open field (Paré 1993;Paré 1996), and demonstrate greater hypo neophagia; that is, the fear of feeding in a novel environment when hungry, than other rat strains (Paré 1994).…”