Verticalization of behavior elicited by dopaminergic mobilization is qualitatively different between C57BL/6J and DBA/2J mice

Abstract

Behavioral effects of dopaminergic stimulation were evaluated in C57BL/6J mice and compared to the effects occurring in DBA/2J mice, an inbred strain with reduced densities of striatal dopamine receptors. Effects of apomorphine (0.5-64 mg/kg) alone and in combination with cocaine (30 mg/kg) were assessed using a time-sampling technique that classified climbing and leaning in separate categories. Locomotion was also assessed in a separate experiment. Climbing occurred in DBA/2J mice only at doses of apomorphine that were 16 times higher than the smallest effective dose in C57BL/6J mice; nevertheless, relative to baseline values, effects were fairly comparable. By contrast, whereas DBA/2J mice showed dose-dependent leaning under apomorphine, C57BL/6J mice exhibited little leaning even at doses not producing climbing, and only after the highest apomorphine dose was leaning significantly increased. Apomorphine was equipotent in inducing gnawing across strains, although somewhat less efficacious in DBA/2J mice. When given alone, cocaine produced significant climbing, but not leaning or gnawing, in either strain. Whereas cocaine potentiated apomorphine-induced climbing and gnawing in both strains, apomorphine-induced leaning was not consistently changed by cocaine in either strain. These effects were not indirectly due to hyperkinesia, since neither apomorphine alone nor apomorphine and cocaine in combination was stimulant; apomorphine alone reduced locomotor activity and attenuated cocaine-induced hyperkinesia. The present data do not support a unitary, purely quantitative, account of insensitivity to dopaminergic stimulation based upon low densities of striatal dopamine receptors in DBA/2J mice. Rather, this constellation of results is suggestive of qualitative interstrain dissimilarities in dopaminergic responsiveness that could reflect organizational differences in receptor populations.

An Improved BAC Transgenic Fluorescent Reporter Line for Sensitive and Specific Identification of Striatonigral Medium Spiny Neurons

“…In addition to locomotor activity, other dopamine-dependent behavioral domains including vertical rearing, stereotypies and time spent in the center region of the OF chamber were assessed (Chandler et al, 1990; Tirelli and Witkin, 1994; Pogorelov et al, 2005). Neither line 6 nor Drd2 -EGFP mice exhibited significant differences in vertical rearing or time spent performing stereotypic movements, either basally or in response to acute cocaine (Figures 2A–D).…”

SEE locomotor behavior test discriminates C57BL/6J and DBA/2J mouse inbred strains across laboratories and protocol conditions.

“…Common view holds that B6 is a high-activity strain, whereas the D2 is an intermediate-activity strain (Cabib, 2002; Crawley et al, 1997). This view, however, seems to represent only a broad average over studies, with some that reported B6 to be significantly more active (e.g., Bolivar, Caldarone, Reilly, & Flaherty, 2000, for females; Elmer, Gorelick, Goldberg, & Rothman, 1996; Gorris & van Abeelen, 1981; Hatcher et al., 2001; Logue, Owen, Rasmussen, & Wehner, 1997), many that did not detect a significant difference in activity (e.g., Bolivar et al, 2000, for males; Cabib & Bonaventura, 1997; Jones, Reed, Radcliffe, & Erwein, 1993; Rocha et al, 1998; Tirelli & Witkin, 1994; Tolliver & Carney, 1995; Womer, Jones, & Erwin, 1994), and at least one (Rogers at al., 1999) that found D2 mice to have significantly higher activity. It should be noted that these studies used different arena sizes (longer dimension of 40–60 cm), arena shapes (square, rectangular, or circular), light conditions (fully illuminated to complete darkness), and tracking techniques (photocells, photobeam, and video).…”

Predictive Value of Grooming Behavior for Development of Dermatitis in Selectively Bred P Rats as a Model of Trichotillomania Hair Pulling Disorder

“…The C57BL/6J mouse and the P rat are currently used as models for addiction studies [61][62][63][64][65][66]. They also consistently test as more anxious in assays to measure depression and anxiety when compared to other rodent models [56].…”

“…The comorbidity of these conditions with the expression of TTM is similar to the presentation seen in humans, further supporting the potential applicability of these rodents as animal models of TTM. The C57BL/6J mouse and the P rat are currently used as models for addiction studies [61][62][63][64][65][66]. They also consistently test as more anxious in assays to measure depression and anxiety when compared to other rodent models [56].…”