Behavioral differences between selectively bred rats: D1 versus D2 receptors in yawning and grooming

Central administration of oxytocin differentially increases yawning, penile erections and scratching in high- (HY) and low-yawning (LY) sublines of Sprague–Dawley rats

“…Thus, increased expression of dopamine receptors in the HY subline might account, at least in part, for the different responses between sublines in yawning and penile erections after administration of oxytocin or D2-like agonists (present results and Eguibar et al, 2003). The dopamine-oxytocin link in the PVN of the hypothalamus is responsible for the correlation between yawning and penile erections induced either spontaneously, by D2-like dopaminergic receptor activation, or after i.c.v.…”

“…Taken together, these data suggest that HY and RHA show similar responses to stress situations and have higher sensitivity to D2-like dopaminergic-or oxytocin-induced yawning, compared to LY and RLA sublines. These results imply that during inbreeding processes of HY and RHA rats, we selected different coping strategies that are opposite to that shown by LY and RLA rats (Melis and Argiolas, 2011;Eguibar et al, 2003;present results).…”

“…For example, oxytocin, administered in the PVN and CA1 fields of the hippocampus, induces a significant increase in yawning and penile erection frequencies (Melis et al, 1986), presumably through activation of the uterine type of oxytocin receptors and subsequent increased activity of brainstem or spinal cord relay neurons (Swanson and Kuypers, 1980). Previous research has shown that D2-like dopaminergic agonists induce higher yawning frequencies in HY rats compared to the LY subline (Urbá-Holmgren et al, 1993;Eguibar et al, 2003). A differential effect in drug-induced yawning between the HY and LY sublines has also been reported after central administration of ACTH 1-24 (Eguibar et al, 2004).…”

“…The high-yawning (HY) subline have an average of 20 yawns/h and the low-yawning (LY) subline yawn only twice per hour (Urbá-Holmgren et al, 1990). Previous research has shown that systemic administration of D2-like dopaminergic agonists or central administration of adrenocorticotrophic hormone fraction 1-24 (ACTH 1-24 ) produces more yawning and penile erections in the HY than the LY subline (Urbá-Holmgren et al, 1993;Eguibar et al, 2003;2004). Furthermore, i.c.v.…”

The grooming analysis algorithm discriminates between different levels of anxiety in rats: potential utility for neurobehavioural stress research

“…Grooming is a frequently performed behaviour by small felids, bovids, cervids and primates (Eckstein and Hart, 2000;Hart and Pryor, 2004), and is an important part of rodent behavioural repertoire (Berridge and Whishaw, 1992;Berridge et al, 1987;Van Erp et al, 1995). In rodents, grooming is a complex, ethologically rich ritual, which normally proceeds in a cephalocaudal direction and consists of several stages, inand de-arousal (Eguibar et al, 2003;Kametani, 1988;Sachs, 1988;Spruijt et al, 1992).…”