In vivo: |
Brain Res. 1977 Nov 18;136(3):513-22. | Effects of the Areca nut constituents arecaidine and guvacine on the action of GABA in the cat central nervous system.[Pubmed: 922499 ] | Arecaidine and guvacine, constituents of the nut of Areca catechu, inhibited the uptake of GABA and beta-alanine, but not that of glycine, by slices of cat spinal cord.
METHODS AND RESULTS:
In cats anesthetised with pentobarbitone, electrophoretic Arecaidine enhanced the inhibitory actions of GABA and beta-alanine, but not those of glycine or taurine, on the firing of spinal neurones. Similarly, electrophoretic guvacine enhanced the inhibition of spinal neurones by GABA but not that by glycine. The uptake of GABA by slices of cat cerebellum was inhibited by Arecaidine, and the effect of electrophoretic GABA on the firing of cerebellar Purkinje cells was enhanced by electrophoretic Arecaidine.
When administered intravenously Arecaidine failed to affect synaptic inhibitions considered to be mediated by GABA. Intravenous Arecaidine had no effect on either spinal prolonged (presynaptic) inhibition (20mg/kg), dorsal root potentials (20mg/kg) or basket cell inhibition of Purkinje cells (250 mg/kg), although topical Arecaidine (6.6-10 x 10(-3) M) blocked this latter inhibition.
CONCLUSIONS:
Large doses of Arecaidine (1 g/kg subcutaneous) marginally reduced the lethal effects of bicuculline in mice but appeared to have little or no anticonvulsant activity. | J Pharm Pharmacol. 2013 Apr;65(4):582-90. | Transport of the areca nut alkaloid arecaidine by the human proton-coupled amino acid transporter 1 (hPAT1).[Pubmed: 23488788 ] | The pyridine alkaloid Arecaidine is an ingredient of areca nut preparations. It is responsible for many physiological effects observed during areca nut chewing. However, the mechanism underlying its oral bioavailability has not yet been studied. We investigated whether the H⁺-coupled amino acid transporter 1 (PAT1, SLC36A1), which is expressed in the intestinal epithelium, accepts Arecaidine, arecoline, isoguvacine and other derivatives as substrates.
METHODS AND RESULTS:
Inhibition of L-[³H]proline uptake by Arecaidine and derivatives was determined in Caco-2 cells expressing hPAT1 constitutively and in HeLa cells transiently transfected with hPAT1-cDNA. Transmembrane transport of Arecaidine and derivatives was measured electrophysiologically in Xenopus laevis oocytes.
Arecaidine, guvacine and isoguvacine but not arecoline strongly inhibited the uptake of L-[³H]proline into Caco-2 cells. Kinetic analyses revealed the competitive manner of L-proline uptake inhibition by Arecaidine. In HeLa cells transfected with hPAT1-cDNA an affinity constant of 3.8 mm was obtained for Arecaidine. Electrophysiological measurements at hPAT1-expressing X. laevis oocytes demonstrated that Arecaidine, guvacine and isoguvacine are transported by hPAT1 in an electrogenic manner.
CONCLUSIONS:
We conclude that hPAT1 transports Arecaidine, guvacine and isoguvacine across the apical membrane of enterocytes and that hPAT1 might be responsible for the intestinal absorption of these drug candidates. |
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