ISSN:
1435-1463
Keywords:
Pipecolic acid
;
GABA
;
Micro-iontophoresis
;
GABA-B receptors
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Several previous studies have suggested a strong GABA-mimetic action of the endogenous brain imino acid, L-pipecolic acid (L-PA). In the present study, these observations were evaluated using electrophysiological and neurochemical methods. In contrast to published data our electrophysiological studies on rat cortical neuronesin situ showed only a weak, but bicuculline-sensitive depressant action of L-PA on cortical neurones. Furthermore, L-PA proved to have no affinity for any of the three components of the GABA-benzodiazepine-chloride channel receptor complex. However, using a modification of published methods a weak affinity for the GABA-B receptor site was demonstrated (IC50=1.8×10−3 M). L-PA showed no anticonvulsive activity in several tests; in particular, it did not protect mice from seizures induced by inhibition of L-glutamate-1-decarboxylase (EC 4.1.1.15: GAD). L-PA had a very weak action on brain GABA levels of mice, and did not modify the rate of GABA synthesis. In conclusion, these results are not compatible with a strongin vivo interaction between L-PA and GABA-mediated inhibitory transmission.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01243346
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