To study the relationship between the density of muscarinic receptor (MR) subtype and the occurrence of bladder instability. The rat model of unstable bladder was established, and the density of MR subtype was determined in normal and unstable bladders. The results showed that there were only m 2 RNA and m 3 RNA present in the detrusor of normal and unstable bladders, and m 1, m 2 or m 3 mRNA subtypes were not detected. In the normal bladder, the amount of m 2 RNA (1 67?0 42) was obviously greater than m 3 RNA (0 64?0 19), and the ratio of them was 2 59∶1. In the unstable bladder, the density of both m 2 and m 3 increased to (2 03?0 65) and (1 53?0 46) respectively, and the increase of m 3 was more significant ( P

To investigate the expression of ? adrenoceptors(? AR) and its possible function in rat detrusor. The relaxation response produced by ? AR subtypes(? 1 , ? 2 , ? 3 AR) agonists or antagonists were examined by means of the in vitro detrusor strip study, and the expression of ? AR subtypes mRNA was investigated in rat detrusor muscle by RT PCR. The selective ? 1 agonist T 0509, ? 2 agonist salbutamol, ? 3 agonist BRL37344A depressed the contractions of the detrusor muscle induced by KCl. The relaxant response to isoproterenol was antagonized by the ? 1 ,? 2 AR antagonists(100?mol/L) and the ? 3 AR antagonists SR59230(1?mol/L).RT PCR, showing that all three subtypes of ? AR subtypes mRNA were expressed in rat detrusor smooth muscles, in which ? 3 AR mRNA occupied 70%. All the ? 1 ,? 2 ,? 3 adrenoceptors participate in mediating relaxation of rat detrusor, among them ? 3 AR is the main one.

To investigate the role of ?and ? 3 adrenoceptors(? 3 AR) in rat detrusor instability secondary to bladder outflow obstruction(BOO). Animal models of detrusor instability were replicated in female rats, the relaxation response produced by ISO and ? 3 AR agonists BRL37344A were examined by means of in vitro detrusor strip study. ? and ? 3 adrenoceptors were detected in bladder specimens with radioligand binding assay. The concentrations of ISO and BRL37344A to produce relaxation were different in normal, stable and instable groups. There was a significant decrease in the density of ? adrenoceptors in the instable group compared with the controls and the stable group (66 23?6 39, 85 85?7 53, and 81 36?6 72 fmol/mg protein, respectively) ( P