Paradoxical locomotor activating effects of kappa-opioid receptor stimulation in the preweanling rat: role of the ventromedial thalamus and superior colliculus.
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.
Zavala
A R
AR
Department of Psychology, California State University, San Bernardino, CA 92407, USA.
Yoshida
S T
ST
Osburn
J R
JR
McDougall
S A
SA
D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer / Q000494:pharmacology; D018712:Analgesics, Non-Narcotic / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D005260:Female; D008297:Male; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology*; D009068:Movement / Q000187:drug effects / Q000502:physiology; D009434:Neural Pathways / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017473:Receptors, Opioid, kappa / Q000819:agonists / Q000378:metabolism*; D013378:Substantia Nigra / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D013477:Superior Colliculi / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D020651:Ventral Thalamic Nuclei / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*
D018712:Analgesics, Non-Narcotic; D017473:Receptors, Opioid, kappa; D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer