THE EFFECTS OF AN IRREVERSIBLE DOPAMINE-RECEPTOR ANTAGONIST, N-ETHOXYCARBONYL-2-ETHOXY-1,2-DIHYDROQUINOLINE (EEDQ), ON THE REGULATION OF MUSCLE TONE IN THE RAT - THE ROLE OF THE SUBSTANTIA-NIGRA
Km. Hemsley et Ad. Crocker, THE EFFECTS OF AN IRREVERSIBLE DOPAMINE-RECEPTOR ANTAGONIST, N-ETHOXYCARBONYL-2-ETHOXY-1,2-DIHYDROQUINOLINE (EEDQ), ON THE REGULATION OF MUSCLE TONE IN THE RAT - THE ROLE OF THE SUBSTANTIA-NIGRA, Neuroscience letters, 251(2), 1998, pp. 77-80
Recent evidence has questioned the view that the increased muscle tone
of Parkinson's disease results solely from reduced release of dopamin
e in the striatum, by emphasising the important role of the substantia
nigra. The aim of the current study was to compare the effects on mus
cle tone of inactivating D-1 and D-2 dopamine receptors throughout the
brain with those seen following their inactivation only in the substa
ntia nigra. Inactivation of dopamine receptors by N-ethoxycarbonyl-2-e
thoxy-1,2-dihydroquinoline injected either intraperitoneally, or bilat
erally into the substantia nigra, resulted in similar increases in mus
cle tone, measured as changes in tonic electromyographic (EMG) activit
y. The magnitude and onset of EMG increases was related to the level o
f dopamine receptor inactivation. The results are consistent with the
hypothesis that nigral dopamine mechanisms play a key role in the main
tenance of muscle tone. (C) 1998 Published by Elsevier Science Ireland
Ltd. AII rights reserved.