The activity of compounds inhibiting neuronal or glial
GABA uptake has been assessed following intracerebroventricular (i.c.v.) or intraperitoneal (i.p.) administration in DBA/2 mice (sound-induced
seizures) or Swiss S mice (
pentylenetetrazol-induced
seizures). Sound-induced
seizures are suppressed by the i.c.v. injection of (+/-)-
nipecotic acid, 3.2 mumol, or (+/-)-cis-4-hydroxynipecotic
acid, 2 mumol, but not by i.p. injection of (+/-)-
nipecotic acid, 3.2 mmol/kg or (+/-)-cis-4-hydroxynipecotic
acid 4 mmol/kg.
Pentylenetetrazol-induced
seizures are not suppressed by i.c.v. injection of (+/-)-
nipecotic acid 1-4 mumol, or (+/-)-cis-4-hydroxynipecotic
acid, 2-4 mumol.
THPO (4,5,6,7-tetrahydroisoxazolo[4.5-c]pyridin-3-ol), 1-5 mumol i.c.v. or 1-4 mmol/kg i.p., protects against sound-induced
seizures. There is no protection against
pentylenetetrazol seizures after i.c.v.
THPO injection, but
THPO, 2-8 mmol/kg i.p., is protective. Among
prodrugs, (+/-)-
nipecotic acid pivaloyloxymethyl
ester protects against sound-induced
seizures, when given i.c.v. (3.2 mumol) or i.p. (1.6-3.2 mmol/kg) and against
pentylenetetrazol seizures when given i.p. (0.5-4 mmol/kg). (+/-)-cis-4-hydroxynipecotic
acid methyl
ester protects against sound-induced
seizures when given i.p. (3.2 mmol/kg), but is only partially protective against
pentylenetetrazol seizures, when given i.p. (4 mmol/kg). Some
prodrugs induce
myoclonus following either i.c.v. or i.p. administration.