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Neurophysiological evidence for tolerance and dependence on opiates: Simultaneous multiunit recordings from septum, thalamus, and caudate nucleus

✍ Scribed by Nachum Dafny


Book ID
102908233
Publisher
John Wiley and Sons
Year
1980
Tongue
English
Weight
647 KB
Volume
5
Category
Article
ISSN
0360-4012

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✦ Synopsis


Abstract

Multiunit activity was recorded simultaneously from the septum (Spt), medial thalamus (PF‐CM complex), and caudate nucleus (CN) in freely behaving rats previously implanted with permanent nichrome semimicroelectrodes (62μ in diameter). A challenge dose of morphine (10 mg/kg) and its antagonist (naloxone 1.0 mg/kg) was examined in the same animals while they were morphine naive and after they had become morphine physically dependent. Electrophysiological observations indicated that it would be possible to identify three physiological phenomena: (1) activity related to morphine dependency; (2) activity related to tolerance; and (3) activity related to withdrawal. Experimental observations yielded three different electrophysiological patterns of activity related to tolerance. Each of the three central sites (Spt, PF‐CM, and CN) exhibited a different response pattern to morphine in morphine physically dependent animals.