EFFECTS OF MORPHINE ON BRAIN POTENTIALS EVOKED BY STIMULATION OF THE TOOTH PULP OF THE DOG

摘要: The actions of morphine and nalorphine antagonism on tooth pulp primary secondary afferent systems were determined in acute dogs. Morphine usually was given intravenously doses 2 mg/kg or 10 mg/kg. Nalorphine 1 2.5 Drug effects the potentials pathway cortically contralateral coronal gyrus brainstem nucleus ventralis posteromedialis medial lemniscus. In general, did not depress amplitude latency responses this system. complex. evoked from enhanced areas surrounding central grey, some diencephalic nuclei (nucleus centralis medialis, medialis dorsalis, lateralis posterior, subparafascicularis), medullary reticular areas, but occasionally depressed, other animals unaffected. latencies dorsalis prolonged spite an enhancement amplitude. Frequently early depression within first few minutes after intravenous administration associated with a marked fall arterial blood pressure. Upon return pressure toward normal 25 administration, subsequent potential occurred. partially antagonized these morphine. human subjects it shown that single shock electrical stimulation above threshold intensity incisors produced transient painful sensation. cortical by sciatic nerve inconsistent. majority had no effect. 0.2 to definite recruiting following various thalamic areas. effects. 0.25 ½ hour statistically significant increase mean control values. It is concluded neural mechanisms analgesia pain are does appear simple blockade impulses arising peripheral receptors can explain analgesic action Its pathways variable. Either occasional depression, effect, observed. considerable theoretical interest predominant