TABLE 1

K_d and B_max for specific [³H]NMS binding in the bladder, submaxillary gland, heart, and colon of rats at 1 to 24 h after oral administration of oxybutynin

Rats received 127 μmol/kg oxybutynin orally and were then sacrificed 1 to 24 h after administration. Specific binding of [³H]NMS (0.06-1.5 nM) in rat tissues was measured. Values are mean ± S.E. of 10 (control) and four to six (oxybutynin) rats. Values in parentheses represent the -fold increase in K_d values relative to controls.

Organs	Time after Oral Oxybutynin	K_d	B_max
	h	pM	fmol/mg protein
Bladder	Control	167 ± 5	158 ± 7
	1	258 ± 34 (1.54)^*	170 ± 34
	3	359 ± 61 (2.15)^***	138 ± 14
	12	189 ± 5	112 ± 13
	24	202 ± 10	129 ± 10
Submaxillary gland	Control	108 ± 3	126 ± 4
	1	377 ± 142 (3.49)^*	92.3 ± 9.6^*
	3	840 ± 166 (7.78)^***	67.8 ± 6.8^***
	12	111 ± 8	54.4 ± 5.7^***
	24	123 ± 9	63.6 ± 13.6^***
Heart	Control	270 ± 8	71.1 ± 1.8
	1	362 ± 52 (1.34)^*	67.0 ± 2.4
	3	349 ± 18 (1.29)^*	61.5 ± 2.3^*
	12	245 ± 25	57.2 ± 1.3^**
	24	253 ± 9	58.6 ± 3.6^**
Colon	Control	152 ± 4	115 ± 9
	1	294 ± 28 (1.93)^**	119 ± 5
	3	370 ± 57 (2.43)^***	120 ± 12
	12	191 ± 30	106 ± 7
	24	170 ± 8	117 ± 5

Asterisks show a significant difference from the control values: ^* P < 0.05; ^** P < 0.01; ^*** P < 0.001.