Yawning and locomotor behavior induced by dopamine receptor agonists in mice and rats

Abstract

Dopaminergic (DA) agonist-induced yawning in rats seems to be mediated by DA D3 receptors, and low doses of several DA agonists decrease locomotor activity, an effect attributed to presynaptic D2 receptors. Effects of several DA agonists on yawning and locomotor activity were examined in rats and mice. Yawning was reliably produced in rats, and by the cholinergic agonist, physostigmine, in both the species. However, DA agonists were ineffective in producing yawning in Swiss–Webster or DA D2R and DA D3R knockout or wild-type mice. The drugs significantly decreased locomotor activity in rats at one or two low doses, with activity returning to control levels at higher doses. In mice, the drugs decreased locomotion across a 1000–10 000-fold range of doses, with activity at control levels (U-91356A) or above control levels [(±)-7-hydroxy-2-dipropylaminotetralin HBr, quinpirole] at the highest doses. Low doses of agonists decreased locomotion in all mice except the DA D2R knockout mice, but were not antagonized by DA D2R or D3R antagonists (L-741 626, BP 897, or PG01037). Yawning does not provide a selective in-vivo indicator of DA D3R agonist activity in mice. Decreases in mouse locomotor activity by the DA agonists seem to be mediated by D2 DA receptors.

Aberrant Dopamine D2-Like Receptor Function in a Rodent Model of Schizophrenia

“…To examine whether postsynaptic D2 receptor function was altered in the MAM model, we examined the locomotor response to quinpirole. Consistent with previous observations, quinpirole produced an initial suppression of spontaneous locomotor activity at both low and high doses (Svensson et al, 1994;Szechtman et al, 1994;Li et al, 2010). Increasing doses of quinpirole produced a biphasic response with an initial decrease in ambulation being followed by robust increases in locomotor activity, again consistent with previous observations (Svensson et al, 1994;Szechtman et al, 1994;Li et al, 2010).…”

“…Consistent with previous observations, quinpirole produced an initial suppression of spontaneous locomotor activity at both low and high doses (Svensson et al, 1994;Szechtman et al, 1994;Li et al, 2010). Increasing doses of quinpirole produced a biphasic response with an initial decrease in ambulation being followed by robust increases in locomotor activity, again consistent with previous observations (Svensson et al, 1994;Szechtman et al, 1994;Li et al, 2010). It is noteworthy that MAM-treated rats were more sensitive to the locomotor-inducing effects of quinpirole, with a majority (75%) of MAM-treated rats displaying robust locomotor activation in response to the 0.1 mg/kg dose (compare with 25% for saline-treated rats; Fig.…”

“…To examine whether postsynaptic D2 receptor function was altered in the MAM model, we examined the locomotor response to quinpirole. Consistent with previous observations, quinpirole produced an initial suppression of spontaneous locomotor activity in control rats (Svensson et al, 1994;Szechtman et al, 1994;Li et al, 2010). It is noteworthy that MAM-treated rats were more sensitive to the locomotor-inducing effects of quinpirole such that they displayed an opposite behavioral response to low doses of quinporole (i.e., locomotor activation compared with suppression).…”

Integrating PET with behavioral neuroscience using RatCAP tomography

“…Activation of D2auto inhibits the synthesis and release of DA (Farnebo and Hamberger , 1971 ;Kehr et al , 1972 ;Starke et al , 1989 ) and increases the reuptake of DA via DA transporters (DAT) (Schmitz et al , 2003 ). D2auto activation by low doses of quinpirole inhibits behavioral activity (Eilam and Szechtman , 1989 ;Depoortere et al , 1996 ;Usiello et al , 2000 ;Li et al , 2010 ). Bello et al (2011) demonstrated that D2auto are important for normal motor function, foodseeking behavior, and sensitivity to the locomotor and rewarding properties of cocaine.…”

Evaluation of Activity Patterns in Quinpirole-Treated Rats

“…The methodology, or adaptations of it, could be similarly used for testing the time course of the effects of dopaminergic drugs with precision of less than one hour and can be used likewise for testing differences of spontaneous a ctivity i n c hronic t reatments o r i nteractions w ith other d rugs, l ike c lomipramine [11], pr ovided that the testing schedules are strictly fixed. Most previous s tudies ha ve measured l ocomotor a ctivity t o t est t he dose-response a nd t ime-course of the pharmacological action of quinpirole [7] [12], while a few have used open field checking activity [13], operant conditioning [14] or s pontaneous activities like s niffing, r earing, g rooming [12] or ya wning [15]. These tests, however, l ack time pr ecision s ince t hey m easure be havior a long e xtended pe riods and t hus stimulus no velty, which is relevant for context-dependent manifestations, is gradually lost.…”