UI - 000214

AU - Cohen SR

AU - Abbott FV

AU - Melzack R

TI - Unilateral analgesia produced by intraventricular morphine

AB - AB - Morphine injected into the lateral ventricle of the rat produced unilateral analgesia in the

formalin test, which involves continuous, moderate pain. In contrast, analgesia was produced bilaterally in

the foot-flick test which involves brief, rapidly rising pain. In the formalin test, intraventricular morphine

produced analgesia in the ipsilateral but not the contralateral hindpaw. Analgesia was achieved with

relatively low doses of morphine (2.5-10.0 micrograms) in the formation test while very high doses (50-200

micrograms) were necessary to produce analgesia in the foot-flick test. These results add to other data

indicating that different neural mechanisms underlie opiate analgesia in different types of pain. Moreover,

they indicate that, in the formation test, the neural mechanisms of morphine analgesia are somatotopically

organized and that forebrain structures are likely to be involved UI - 84258471

SO - Brain Res 1984;303:277-287