Electrophysiological observations on the effects of potassium ions on the response of intradental nerves to dentinal tubular flow in the cat.
OBJECTIVE
To determine the effects of K(+) on the sensitivity of sensory receptors in teeth to fluid flow through dentine.


METHODS
Evoked discharges were recorded from intradental nerves in anaesthetised cats during the application of 5s hydrostatic pressure stimuli to exposed dentine through either normal Ringer's or Ringer's containing up to 255 mmol/lK(+). The stimuli ranged between -500 and +500 mm Hg.


RESULTS
The number of impulses evoked by a positive pressure stimulus increased, and the latency of the response decreased, as either the pressure or the K(+) concentration of the Ringer's was increased. The response to a negative pressure stimulus applied 2s after a positive pressure pulse of equal but opposite amplitude decreased as either the intensity of the stimulus or the K(+) concentration of the Ringer's was increased.


CONCLUSIONS
Potassium ions that were transported into the dentine and pulp by bulk flow during the application of positive pressure stimuli increased the sensitivity of the receptors to inward tubular flow but decreased their sensitivity to outward flow.
Department of Physiology, School of Medical Sciences, University of Bristol, University Walk, Bristol, UK. dnooi002@chiangmai.ac.th
S
S
Wanachantararak
N
N
Vongsavan
B
B
Matthews
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D002415:Cats; D003782:Dental Pulp / Q000098:blood supply / Q000294:innervation; D003804:Dentin / Q000294:innervation*; D003807:Dentin Sensitivity / Q000503:physiopathology*; D019234:Dentinal Fluid / Q000502:physiology*; D004558:Electric Stimulation; D057446:Hydrodynamics; D006874:Hydrostatic Pressure; D007477:Ions; D007552:Isotonic Solutions; D008465:Mechanoreceptors / Q000187:drug effects* / Q000502:physiology; D009433:Neural Inhibition; D009566:Nitrates / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology*; D011189:Potassium Chloride / Q000494:pharmacology; D017680:Potassium Compounds / Q000494:pharmacology; D011930:Reaction Time; D012032:Refractory Period, Electrophysiological; D000077331:Ringer's Solution
D007477:Ions; D007552:Isotonic Solutions; D009566:Nitrates; D017680:Potassium Compounds; D011189:Potassium Chloride; D000077331:Ringer's Solution; C023844:potassium nitrate; D011188:Potassium