Document Detail


Action of dextroamphetamine on dopamine sensitive cells in the snail brain.
MedLine Citation:
PMID:  7250187     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Presynaptic and postsynaptic actions of dextroamphetamine (DEX) were studied on dopamine (DA) sensitive neurons of the subesophageal ganglion of the garden snail Helix aspersa utilizing standard microelectrode techniques. Dextroamphetamine (5.5 X 10(-7)-10(-4)M) produced effects on DA-sensitive neurons similar to that caused by DA (5.5 X 10(-7)-10(-4)M). On cells excited by DA, surfused DEX (5.5 X 10(-7)M) caused an excitation that could be blocked by chlorpromazine (0.5-1 X 10(-6)M) or haloperidol (0.5-1 X 10(-6)M). Elevating the extracellular Mg2+ from 4 to 20 mM reduced the depolarization caused by DEX from 11 to 2.5 mV without affecting the response to DA. The response remaining is attributed to a direct response to DEX on DA receptors. Surfused DEX caused an inhibition of cells inhibited by DA. Both DA and DEX effects were selectively blocked by dihydroergotamine (0.5-1 X 10(-6)M). Elevating the [Mg2+] decreased the hyperpolarization caused by DEX from 11 to 3 mV without affecting the DA response. The effect of elevated magnesium in decreasing responses to surfused DEX suggests that the primary action of DEX is at the nerve terminal to cause DA release. Iontophoretic application of DEX caused minimal excitation or inhibition of DA neurons. This is attributed to the fact that DA receptors at the site of drug application are not associated with synaptic innervation. The response obtained with iontophoretically applied DEX suggest a weak direct action on DA receptors.
Authors:
J C Hancock; J M Guillot
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  European journal of pharmacology     Volume:  71     ISSN:  0014-2999     ISO Abbreviation:  Eur. J. Pharmacol.     Publication Date:  1981 May 
Date Detail:
Created Date:  1981-09-15     Completed Date:  1981-09-15     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  1254354     Medline TA:  Eur J Pharmacol     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  201-9     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Animals
Brain / drug effects
Dextroamphetamine / pharmacology*
Dopamine / pharmacology
Helix (Snails)
Magnesium / pharmacology
Membrane Potentials / drug effects
Neurons / drug effects
Norepinephrine / secretion
Receptors, Dopamine / drug effects*
Grant Support
ID/Acronym/Agency:
MH 25361-01/MH/NIMH NIH HHS; NS 11019-01/NS/NINDS NIH HHS
Chemical
Reg. No./Substance:
0/Receptors, Dopamine; 51-41-2/Norepinephrine; 51-64-9/Dextroamphetamine; 7439-95-4/Magnesium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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