Isolation of synaptosomes from the rat urinary bladder.

Synaptosomes are nerve-end particles (NEP) isolated by using the technique of differential centrifugation. The synaptosome offers a good model for biochemical and pharmacological studies of the nerve endings. No report has been made on synaptosome isolation from the urinary bladder. The purpose of our work was to develop the use of synaptosome in the research of neurophysiology and neuropharmacology of the urinary bladder. Synaptosome-rich fraction was prepared from tissue homogenate of male Wistar rat urinary bladder by differential centrifugation (1000, 17,000 and 100,000 g) with discontinuous sucrose gradient. Electron microscopy showed synaptosomes as thin-walled bags containing a large number of synaptic vesicles. Two types of synaptosomes were easily discerned: those containing small agranular vesicles, and those containing dense-cored vesicles. The acetylcholine, norepinephrine, epinephrine and dopamine contents in the preparation were measured by the method of high-performance liquid chromatography. The respective concentrations were 300.4 +/- 30.1, 962.8 +/- 58.5, 617.3 +/- 59.8 and 1354.8 +/- 144.2 pmol/mg synaptosomal protein. In conclusion, it has been demonstrated that synaptosome-rich fractions can be prepared from the rat urinary bladder. Thus it is possible to apply this methodology for the investigation of the neurobiology of urinary bladders.