Abstract
PNU-151774E [(S)-(+)-2-(4-(3-fluorobenzyloxy) benzylamino) propanamide, methanesulfonate] is a structurally novel anticonvulsant having Na+ channel-blocking and glutamate release-inhibiting properties, as well as being a MAOBinhibitor. Its anticonvulsant activity was evaluated in the maximal electroshock (MES) test and in chemically induced seizures (bicuculline, BIC; picrotoxin, PIC; 3-mercaptopropionic acid, 3-MPA; pentylenetetrazole, PTZ; strychnine, STRYC). Behavioral toxicity was evaluated in the rotorod test with measurements of spontaneous locomotor activity and passive avoidance responding. The anti-MES activity of PNU-151774E in both mice and rats, respectively, produced ED50 values of 4.1 mg/kg and 6.9 mg/kg after i.p. administration or 8.0 mg/kg and 11.8 mg/kg after p.o. administration. Oral anti-MES activity in rats peaked between 1 and 2 h after administration and was evident up to 4 h. This activity was related to brain levels of unchanged drug which peaked at 37 mM within 1 h. Oral ED50 values (mg/kg) effective in blocking tonic extension seizures by chemical convulsants in mice were: BIC (26.9), PIC (60.6), 3-MPA (21.5), STRYC (104.1) and PTZ (26.8). This potency was associated with high therapeutic indices relative to: MES (78.2), BIC (23.3), PIC (10.3), 3-MPA (29.1) and STRYC (6.0). No evidence of tolerance to anti-MES activity after repeated dosing was observed. PNU-151774E did not show anti-absence seizure activity as assessed by i.v. infusion of PTZ. PNU-151774E impaired spontaneous activity in rats only at the oral rotorod ED50 dose of 700 mg/kg p.o. PNU-151774E did not impair passive avoidance responding at doses up to 40 times the oral MES ED50 dose in rats. These results indicate that PNU-151774E is an anticonvulsant effective in various seizure models with a wide therapeutic window, and with a low potential to induce tolerance and locomotor or cognitive side effects.
Footnotes
-
Send reprint requests to: Robert A McArthur, PhD, CNS Discovery Research, 725/209-407, Pharmacia & Upjohn, Inc., 301 Henrietta Street, Kalamazoo, MI, 49007.
- Abbreviations:
- PNU-151774E
- [(S)-(+)-2-(4-(3-fluorobenzyloxy) benzylamino) propanamide, methanesulfonate]
- MES
- maximal electroshock
- BIC
- bicuculline
- PIC
- picrotoxin
- 3-MPA
- 3-mercaptopropionic acid
- PTZ
- pentylenetetrazole
- STRYC
- strychnine
- AED
- antiepileptic drugs
- CBZ
- carbamazepine
- PHT
- phenytoin
- PB
- phenobarbital
- VPA
- valproate
- DZP
- diazepam
- LTG
- lamotrigine
- TI
- Therapeutic Index
- (+)MK-801 (+)-5-methyl-10
- 11-dihydro-5H-dibenzo[a,d]cyclohepten-5–10-imine maleate
- HPLC
- high-performance liquid chromatography
- NIH-NINDS
- National Institutes of Health-National Institute of Neurological Disorders and Stroke
- Received August 4, 1997.
- Accepted January 5, 1998.
- The American Society for Pharmacology and Experimental Therapeutics
JPET articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|