SPECIFICITY OF AMPHETAMINE INDUCED RELEASE OF NOREPINEPHRINE AND SEROTONIN FROM RAT-BRAIN INVITRO

  • 1 January 1977
    • journal article
    • research article
    • Vol. 18  (4) , 627-644
Abstract
Incubation of normal rat cortical or brain stem tissue with 3H-NE (norepinephrine) or 3H-5-HT (5-hydroxytryptamine) and subsequent exposure to amphetamine produced a concentration-related release of the transmitters from tissue stores into the incubation media. Although pretreatment with the catecholamine neurotoxin 6-hydroxydopamine (6-OHDA) reduced the retention of 3H-NE in both ot these tissues, the proportion of 3H-NE released by amphetamine was attenuated only in cortical tissue. Pretreatment with the serotonergic neurotoxin, 5,6-dihydroxytryptamine (5,6-DHT) had no effect on the retention or release of 3H-NE in cortical or brain stem tissue. Pretreatment with 5,6-DHT reduced the retention of 3H-5-HT in the cortex and brain stem, but the release of 3H-5-HT was significantly attenuated only in the latter tissue. 6-OHDA pretreatment increased the retention and proportion of cortical 3H-5-HT released by amphetamine but reduced the release of brain stem 3H-5-HT in the absence of an effect on retention. The in vitro release of 3H-NE from the cerebral cortex occurs primarily from catecholamine and not serotonergic neurons; the cortidal release of 3H-5-HT is not an event specific to serotonergic nerve terminals. The release of 3H-5-HT from brain stem does not appear to be restricted to the serotonergic cell bodies since its release was attenuated by 5,6-DHT and 6-OHDA.