Zavala A R, Yoshida S T, Osburn J R, McDougall S A
Department of Psychology, California State University, San Bernardino, CA 92407, USA.
Brain Res Dev Brain Res. 2002 Dec 15;139(2):301-6. doi: 10.1016/s0165-3806(02)00516-3.
Stimulating kappa-opioid receptors in the substantia nigra pars reticulata robustly increases the locomotor activity of preweanling rats. To determine whether nigrothalamic and nigrotectal connections are necessary for this kappa-opioid-mediated locomotor activity, preweanling rats were given a systemic injection of saline or 5 mg/kg U50,488 (a kappa-opioid receptor agonist) 2 days after receiving sham or bilateral electrolytic lesions of the ventromedial thalamus (VMT) or superior colliculus (SC). Results showed that lesions of the VMT and SC attenuated the U50,488-induced locomotor activity of preweanling rats, indicating that the locomotor activating effects of kappa-opioid receptor stimulation require that nigrothalamic and nigrotectal connections be intact.
