Dopaminergic modulation of kappa opioid-mediated ultrasonic vocalization, antinociception, and locomotor activity in the preweanling rat.
The purpose of this study was to determine whether dopamine (DA) systems modulate kappa opioid-mediated ultrasonic vocalizations (USVs), antinociception, and locomotion in young rats. Seventeen-day-old rats were injected with the kappa agonist U-50,488 (0.0-7.5 mg/kg) and saline, the D2-like receptor agonist R(-)-propylnorapomorphine (NPA; 0.1 or 1.0 mg/kg), the indirect DA agonist cocaine (10 or 20 mg/kg), or the DA antagonist flupenthixol (0.25 or 0.5 mg/kg). USVs and locomotion were measured for 6 min, with antinociception being assessed with a tail-flick test. Kappa receptor stimulation produced analgesia and increased USVs and locomotion. U-50,488-induced analgesia was potentiated by NPA, whereas U-50,488-induced USVs were attenuated by both DA agonists. NPA and flupenthixol depressed U-50,488's locomotor effects. These results show that DA systems interact with kappa opioid systems to modulate USVs, antinociception, and locomotion in preweanling rats.
Nazarian
A
A
Department of Psychology, California State University, San Bernardino 92407-2397, USA.
Rodarte-Freeman
A L
AL
McDougall
S A
SA
D000818:Animals; D004298:Dopamine / Q000378:metabolism*; D018491:Dopamine Agonists / Q000008:administration & dosage / Q000378:metabolism*; D004924:Escape Reaction / Q000187:drug effects*; D005260:Female; D008124:Locomotion / Q000187:drug effects*; D008297:Male; D017288:Pain Threshold / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017473:Receptors, Opioid, kappa / Q000819:agonists* / Q000378:metabolism; D014828:Vocalization, Animal / Q000187:drug effects*
D018491:Dopamine Agonists; D017473:Receptors, Opioid, kappa; D004298:Dopamine