Kinins and epithelial ion transport in the alimentary tract

Kinin effects on epithelial electrogenic ion transport are reviewed, with r eference to the alimentary tract. The transported ion is usually chloride, but some epithelia also transport bicarbonate. The key components of the tr ansport system are the sodium-potassium-chloride cotransporter, Na+-K+ ATPa se (both located basolaterally) and the CFTR chloride channel (located apic ally). Activation of K+-channels in both membranes may secondarily affect t he anion transport mechanism. The types of kinin receptors that cause chlor ide secretion, the second messengers involved and the possible functional r esponsibilities of the kinin-activated secretory mechanism are discussed.