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DEPRESSION OF EVOKED POTENTIALS IN BRAIN SLICES BY ADENOSINE COMPOUNDS
Author(s) -
SCHOLFIELD C.N.
Publication year - 1978
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1978.tb09752.x
Subject(s) - adenosine , neuroscience , electric stimulation , depression (economics) , chemistry , medicine , psychology , stimulation , economics , macroeconomics
1 A study has been made of the action of adenosine on surface slices of guinea‐pig olfactory cortex in vitro . 2 With extracellular recordings from the pial surface and stimulation of the presynaptic input, the lateral olfactory tract (LOT) generated a monosynaptic negative wave representing dendritic excitatory potentials. This negative wave was depressed by bath application of 1 μ m adenosine with increasing effect up to 1 m m . Adenosine 5′‐triphosphate (ATP), adenosine 5′‐monophosphate (AMP) and cyclic adenosine 3′,5′‐monophosphate (cyclic AMP) had similar depressant actions. Adenine and guanosine were very weak depressants. 3 Theophylline concentrations in the range 10 μ m to 3 m m progressively antagonized the action of adenosine. 4 Dibutyryl cyclic AMP (100 μ m ) and agents which increase intracellular cyclic AMP were not depressants, suggesting that the action of adenosine was not cyclic AMP‐mediated. 5 Intracellular recordings confirmed the depressant effect of adenosine on excitatory potentials generated by LOT stimulation and also showed that postsynaptic action potentials and the membrane of the soma were unaffected by adenosine. 6 Since presynaptic action potentials were also unaffected by adenosine, these experiments suggest that adenosine reduces excitatory transmission at LOT synapses and fortifies the idea that adenosine has a ‘neurohumoral’ action.