Characterization of in vivo dopamine release as determined by brain microdialysis after acute and subchronic implantations: methodological aspects.
Infusion of tetrodotoxin (TTX) through the dialysis membrane and perfusion with calcium-free Ringer solution (calcium depletion) were used to evaluate the dopamine release determined by in vivo brain dialysis. Several hours after implantation, the dopamine release recorded by the U-shaped cannula did not respond to calcium depletion and was only partly (approximately 50%) TTX dependent. The half-life of the TTX-independent dopamine overflow was determined to be 2 h. In contrast, when a transstriatal cannula was used, the dopamine output displayed calcium and TTX dependency. Differences in the dimensions of the two types of probes are a likely explanation for the observed effects. Twenty-four hours after implantation, both types of cannula fulfilled the criteria of calcium and TTX dependency. The results indicate that infusion of TTX-containing or calcium-free Ringer solution can be used to estimate the functional damage caused by the implantation of the cannula.
Westerink
B H
BH
Department of Medicinal Chemistry, State University of Groningen, The Netherlands.
De Vries
J B
JB
D000818:Animals; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D002118:Calcium / Q000494:pharmacology; D002404:Catheterization / Q000009:adverse effects / Q000295:instrumentation; D003956:Dialysis / Q000379:methods*; D004298:Dopamine / Q000378:metabolism*; D004867:Equipment Design; D051381:Rats; D011919:Rats, Inbred Strains; D013779:Tetrodotoxin / Q000494:pharmacology; D013997:Time Factors
D013779:Tetrodotoxin; D002118:Calcium; D004298:Dopamine