title: Uptake and release of [3H]adenosine in human dental pulp.
abstract: The purpose of this study was to examine the uptake and release of adenosine in human dental pulp. Pulp was removed from extracted teeth and incubated in [3H]adenosine (0.02-3.2 micromol/l) for 30-90 min, washed for 30 min and the residual [3H]adenosine extracted and assayed. At 0.02 and 0.4 micromol/l the uptake was saturated after 30 min, whereas at 3.2 micromol/l it was not, even after 90 min. Destruction of the sympathetic nerves by 6-hydroxydopamine prior to incubation in [3H]adenosine (0.4 micromol/l) decreased the uptake of [3H] by 40%. Addition of S(4-nitrobenzyl)-6-thioguanosine (NBTG; 0.1 micromol/l), an inhibitor of adenosine uptake, blocked 90% of the uptake. Electrical stimulation of sympathetic nerves following incubation of pulp in [3H]adenosine (0.4 micromol/l) increased the overflow of [3H] into the medium superfusing the tissue segments. NBTG (0.1 micromol/l) had no effect on this overflow, whereas denervation with 6-hydroxydopamine prior to incubation decreased the overflow by 85%. Although the contribution of post-junctional elements, such as smooth muscle, to this release was not determined it is proposed that most of the purine released was derived from sympathetic nerves.
authors.affiliation: Dental School, Faculty of Health Sciences, The University of Adelaide, Adelaide 5005, South Australia.
authors.forename: V
authors.initials: V
authors.lastname: Marino
authors.forename: D A S
authors.initials: DA
authors.lastname: Parker
mesh_terms: D000241:Adenosine / Q000493:pharmacokinetics*; D046508:Culture Techniques; D003782:Dental Pulp / Q000294:innervation / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D006801:Humans; D011687:Purines / Q000378:metabolism; D013564:Sympathetic Nervous System / Q000378:metabolism / Q000502:physiology; D014316:Tritium
chemical_list: D011687:Purines; D014316:Tritium; D000241:Adenosine; C030985:purine