Basic Research - Neurourology & LUTS/BPH & Others(구연) (NP-012) 백서요도에서 요자제기전에 관한 베타3 수용체의 역할 ¹대구 파티마병원 비뇨기과, ²피츠버그대학교 의과대학 비뇨기과학교실 권준범¹², 스즈키타카히사²,타카오카에이이치로²,시미즈노부타카²,타카이슌², 요시무라나오키² Purpose: To investigate the effect of mirabegron and selective β3-adrenoceptor antagonists on the urethral contractile function using female rats. Material and Methods: Female SD rats were divided into 3 groups. In group A, 2 mg/kg and 10 mg/kg mirabegron were administered intravenously (IV). In group B, 50 µg/kg L-748,337, a selective β3-receptor antagonist, was injected IV prior to 10 mg/kg mirabegron. In group C, 3 mg/kg propranolol and 50 µg/kg L-748,337 were injected IV prior to mirabegron. LPP (leak point pressure), UBP (urethral baseline pressure) and dUP (differential values of urethral pressure during intravesical pressure elevation) were measured before and after drug administration. Results: In group A, LPP, UBP, and dUP were not changes after 2 mg/kg mirabegron, but showed significant decreases in these 3 parameters after 10 mg/kg mirabegron. In group B, L-748,337 made significant increase only in UBP. However, subsequent 10 mg/kg mirabegron reduced all the parameters significantly. In group C, any of 3 parameters were not changed by the combined administration of propranolol and L-748,337. But mirabegron following these combination still reduced LPP, UBP, and dUP. Conclusions: β3-adrenoceptors play a minor role in the control of urethral baseline tone and reflex contractions of the urethral sphincter muscles. Mirabegron can induce urethral sphincter relaxation through β3-receptor-independent mechanisms at a high dose, possibly through interactions with other receptor types such as α1-adrenoceptors. keywords : Mirabegron, Adrenoceptor, Urethra