SYSTEMIC AMPICILLIN DIMINISHES FORMALIN-INDUCED NOCICEPTION IN RATS

The purpose of the present study was to evaluate the antinociceptive effect of the ampicillin using the behavioural nociceptive response induced by formalin in rats. We analysed single and repeated pre-treatment with increasing doses of ampicillin. Acute intraperitoneal administration of ampicillin (100 - 800 mg/kg bw, ip, reduced the second, but not the first phase of formalininduced flinching behaviour, which was interpreted as antinociception. Moreover, repeated pre-treatment with ampicillin (100 - 800 mg/kg bw, ip) for 1, 3 and 7 days reduced the second phase of the formalin test. Our data indicate that ampicillin induces antinociception in the rat formalin test after acute and repeated treatment. Since previous studies reported that ampicillin upregulates glutamate transporter 1 (GLT-1), our data suggest that ampicillin induces antinociception through GLT-1 upregulation.