Alterations of the calcium concentration in cultured smooth muscle cells of the lower urinary tract following pharmacological stimulation

Purpose: Function of the lower urinary tract depends on the coordinated act ion of several smooth and striated muscles. This coordination is achieved b y differential innervation of the distinct muscles by adrenergic, cholinerg ic and NANC nerve fibres. Evaluation of the distribution of functional neur otransmitter receptors is necessary to achieve a complete understanding of this organ system. However, these studies cannot be performed in situ, espe cially not in the human. Material and Methods: Therefore, smooth muscle cells were cultured from dif ferent regions of the lower urinary tract of humans and guinea pigs. These cells were used in stimulation experiments with several neuropharmaca. The changes in intracellular free calcium concentration were used to monitor st imulation. Concentration changes were visualized by the fluorescent dye fur a-2 and recorded by calcium imaging. Results: Smooth muscle cells cultured from different regions of the lower u rinary tract varied in respect to their calcium response. Cells taken from the bladder dome reacted primarily upon carbachol, ATP and histamine with i ntracellular calcium elevations, whereas cells from bladder outlet and pros tate were frequently stimulated by dopamine and ATP, seldom by carbachol, n orepinephrine and histamine. Conclusions: From these experiments we conclude: 1. smooth muscle cells can be cultured from different muscles of the lower urinary tract, 2. those ce lls express functional neurotransmitter receptors, 3. cells of human and gu inea pig origin behave similarly, in principle, 4. depending on their origi n the cells express a different spectrum of neurotransmitter receptors, 5. this cell culture system is especially useful for testing new pharmacologic al substances.