Effects of high pressure on striatal dopamine release in freely moving rats: a microdialysis study.
When human divers and experimental animals are exposed to high pressure of helium-oxygen mixture, they develop the high pressure neurological syndrome, characterized by nausea, vertigo, tremor, myoclonus, EEG modifications and convulsions. Free-moving rats were stereotaxically implanted in the anterior caudate nucleus with a microdialysis probe to measure dopamine, dihydroxyphenylacetic acid and homovanillic acid levels during different phases of a simulated dive up to 5.1 MPa. Compression was found to cause an increase in extracellular dopamine and dihydroxyphenylacetic acid concentrations, but not in homovanillic acid. This represents a specific effect of high pressure on the dopaminergic pathway. Recent findings on D2 autoreceptors, showing a decrease in receptor affinity under pressure, allow us to conclude that pressure increases dopamine synthesis through a direct action on D2 autoreceptors.
Requin
M
M
Department of Neurochemistry, Centre d'Etudes et de Recherches Biophysiologiques Appliquées à la Marine, Toulon, France.
Risso
J J
JJ
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D003342:Corpus Striatum / Q000378:metabolism*; D003956:Dialysis; D004298:Dopamine / Q000378:metabolism*; D006610:High Pressure Neurological Syndrome / Q000378:metabolism*; D006719:Homovanillic Acid / Q000378:metabolism; D008297:Male; D009434:Neural Pathways / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013238:Stereotaxic Techniques
D015102:3,4-Dihydroxyphenylacetic Acid; D004298:Dopamine; D006719:Homovanillic Acid