ISOLATION OF SYNAPTOSOMES FROM THE RAT URINARY-BLADDER

Synaptosomes are nerve-end particles (NEP) isolated by using the techn ique of differential centrifugation. The synaptosome offers a good mod el for biochemical and pharmacological studies of the nerve endings. N o report has been made on synaptosome isolation from the urinary bladd er. ?he purpose of our work was to develop the use of synaptosome in t he research of neurophysiology and neuropharmacology of the urinary bl adder. Synaptosome-rich fraction was prepared from tissue homogenate o f 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 dis cerned: those containing small agranular vesicles, and those containin g 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 concentratio ns 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 demonst rated that synaptosome-rich fractions can be prepared from the rat uri nary bladder. Thus it is possible to apply this methodology for the in vestigation of the neurobiology of urinary bladders.