NMDA receptors in the rostral and intermediate-caudal striatum play an opposite role in regulation of the muscle tone in rats.
The aim of the study was to assess the contribution of the NMDA receptors in the caudate-putamen to the regulation of the muscle tone. The experiment was carried out on male Wistar rats. The hind foot of a rat was flexed or extended at the ankle joint by 25 degrees and the resistance of the foot to passive movements was measured. Haloperidol (1 mg/kg ip) induced the muscle rigidity. The competitive antagonist of NMDA receptors, (+/-)-2-amino-5-phosphonopentanoic acid (AP-5), injected in doses of 2 and 5 micrograms/0.5 microliter bilaterally into rostral regions of the caudate-putamen, inhibited the muscle rigidity induced by haloperidol. In contrast, AP-5 injected bilaterally in the same doses into the intermediate-caudal region of the caudate-putamen in rats not pretreated with haloperidol, induced muscle rigidity. The present results seem to suggest that NMDA receptors localized in the rostral and intermediate-caudal regions of the caudate-putamen play an opposite role in regulation of the muscle tone in rats.
Ossowska
K
K
Department of Neuro-Psychopharmacology, Polish Academy of Sciences, Kraków, Poland.
Konieczny
J
J
D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000818:Animals; D002421:Caudate Nucleus / Q000502:physiology*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D006220:Haloperidol / Q000494:pharmacology; D008297:Male; D009127:Muscle Rigidity / Q000503:physiopathology; D009129:Muscle Tonus / Q000187:drug effects / Q000502:physiology*; D011699:Putamen / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects / Q000502:physiology*
D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D015763:2-Amino-5-phosphonovalerate; D006220:Haloperidol