Table 1.

Unidirectional and net fluxes of Na⁺ and Cl⁻ across rat distal colon:effect of mucosal amiloride and butyrate

	G	ISC	JNa,ms	JNa,sm	JNa,net	JCl,ms	JCl,sm	JCl,net
Control
Basal	7.7 ± 0.4	1.4 ± 0.2	6.8 ± 0.4	3.7 ± 0.2	3.0 ± 0.2	4.6 ± 0.5	1.7 ± 0.4	2.9 ± 0.4
Amiloride	7.9 ± 0.4n.s.	1.3 ± 0.2n.s.	6.2 ±0.3n.s.	3.8 ± 0.3n.s.	2.4 ± 0.3n.s.	5.1 ± 0.5n.s.	2.3 ± 0.5n.s.	2.8 ± 0.3n.s.
Butyrate
Basal	9.3 ± 0.4†	0.7 ± 0.1‡	11.0 ± 0.6§	5.0 ± 0.4*	6.1 ± 0.5§	8.8 ± 0.7§	3.8 ± 0.2§	5.0 ± 0.6*
Amiloride	9.1 ± 0.4n.s.	0.6 ± 0.1n.s.	11.3 ± 0.8n.s.	4.7 ± 0.6n.s.	6.7 ± 0.7n.s.	9.0 ± 1.0n.s.	3.8 ± 0.5n.s.	5.2 ± 0.6n.s.

G,conductance (mS cm⁻²);I^SC,short-circuit current (μmol h⁻¹ cm⁻²);J_Na,ms and J_Cl,ms are Na⁺ and Cl⁻ flux in the mucosa-to-serosa direction;J_Na,sm and J_Cl,sm are Na⁺and Cl⁻ flux in the serosa-to-mucosa direction;J_Na,net and J_Cl,net are net flux of Na⁺ and Cl⁻ (all fluxes in μmol h⁻¹cm⁻²).Control:J_net(n =8)and G (n =16);butyrate:J_net (n =11)and G (n =22).Amiloride was always added to the mucosal bath solution after three 15 min flux periods. Significance refers to comparison of post-amiloride with the basal condition in each group,and also between the two basal conditions

^*P > 0.05

^†P > 0.01

^‡P > 0.001

^§P > 0.0001

^n.s.not significantly different. Values are given as means ±s.e.m.