ADX71441, a novel, potent and selective positive allosteric modulator of the GABA(B) receptor, shows efficacy in rodent models of overactive bladder.
OBJECTIVE
The GABAB receptor agonist baclofen reduces urethral resistance and detrusor overactivity in patients with spasticity. However, baclofen's side effects limit its use for the treatment of overactive bladder (OAB). Here, we tested a novel GABAB positive allosteric modulator (PAM) ADX71441 in models of OAB in mice and guinea pigs.


METHODS
Mice were left untreated or given (p.o.) vehicle (1% CMC), ADX71441 (1, 3, 10 mg kg(-1) ) or oxybutynin (100 mg kg(-1) ; Experiment 1) or vehicle (1% CMC), baclofen (1, 3, 6 mg kg(-1) ) or oxybutynin (Experiment 2). Treated mice were then overhydrated with water, challenged with furosemide, before being placed into micturition chambers and monitored for urinary parameters. In anaesthetized guinea pigs, intravesical infusion of acetic acid was used to induce OAB and the effects of ADX71441 (1, 3 mg kg(-1) ) or baclofen (1 mg kg(-1) ), administered i.v., on cystometric parameters were monitored.


RESULTS
In mice, 10 mg kg(-1) ADX71441 increased urinary latencies, reduced the number of urinary events and the total and average urinary volumes. In guinea pigs, ADX71441 (1 and 3 mg kg(-1) ) increased the intercontraction interval (ICI) and bladder capacity (BC), and reduced micturition frequency (MF) compared to vehicle. At 3 mg kg(-1) ADX71441 completely inhibited the micturition reflex and induced overflow incontinence in five out of 10 animals. Baclofen slightly increased ICI and BC and reduced MF.


CONCLUSIONS
Our findings demonstrate, for the first time, that a GABAB PAM has potential as a novel approach for the treatment of OAB.
Addex Therapeutics SA, Geneva, Switzerland.
M
M
Kalinichev
S
S
Palea
H
H
Haddouk
I
I
Royer-Urios
V
V
Guilloteau
P
P
Lluel
M
M
Schneider
M
M
Saporito
S
S
Poli
D000081:Acetamides; D000818:Animals; D001426:Bacterial Proteins / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use*; D004195:Disease Models, Animal; D005260:Female; D006168:Guinea Pigs; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018080:Receptors, GABA-B / Q000378:metabolism*; D014157:Transcription Factors / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use*; D016896:Treatment Outcome; D014227:Triazines; D053201:Urinary Bladder, Overactive / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology
C000592313:ADX71441; D000081:Acetamides; D001426:Bacterial Proteins; D018080:Receptors, GABA-B; D014157:Transcription Factors; D014227:Triazines
GABAB; allosteric modulation; baclofen; micturition; overactive bladder; oxybutynin; urinary bladder