Role of K+ATP channels, endothelin A receptors, and effect of angiotensin II on blood flow in oral tissues.
K+(ATP) channels are involved in CGRP-mediated vasodilation and in the vasoconstriction induced by endothelin or angiotensin II. In this study, we examined the effects of a K+(ATP) channel antagonist and an ET(A) receptor antagonist on resting blood flow in the pulp and gingiva, and observed their role in the vasodilation induced by tooth stimulation. We also investigated whether receptors for angiotensin II exist in the pulp and gingiva. Blood flow was measured with laser-Doppler flowmetry. Under control conditions, the K+(ATP) channel antagonist and angiotensin II caused a significant drop in blood flow in both target tissues. Blocking of ET(A) receptor did not change basal blood flow. The vasodilation observed after tooth stimulation remained unchanged following blockade of K+(ATP) channels and ET(A) receptors. Analysis of the data shows that open K+(ATP) channels exist during resting conditions in the pulp and gingiva, but that CGRP seems to induce vasodilation mainly via mechanisms other than K+(ATP) channels. ET(A) and AT(1) receptors are found in the pulp and gingiva, but ET(A) receptors are not involved in modulation of a basal vascular tone in these tissues or in the vasodilation observed after tooth stimulation.
Berggreen
E
E
Department of Physiology, Arstadveien 19, University of Bergen, N-5009 Bergen, Norway. elle.berggreen@fys.uib.no
Heyeraas
K J
KJ
D000255:Adenosine Triphosphate; D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D003782:Dental Pulp / Q000098:blood supply / Q000187:drug effects*; D004558:Electric Stimulation; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1 / Q000037:antagonists & inhibitors; D005260:Female; D005289:Ferrets; D005881:Gingiva / Q000098:blood supply / Q000187:drug effects; D005905:Glyburide / Q000494:pharmacology; D017078:Laser-Doppler Flowmetry; D016555:Matched-Pair Analysis; D010456:Peptides, Cyclic / Q000494:pharmacology; D026902:Potassium Channel Blockers / Q000494:pharmacology*; D015221:Potassium Channels / Q000187:drug effects*; D044022:Receptor, Endothelin A; D011945:Receptors, Angiotensin / Q000187:drug effects; D017466:Receptors, Endothelin / Q000187:drug effects*; D012039:Regional Blood Flow / Q000187:drug effects; D018709:Statistics, Nonparametric; D014664:Vasodilation; D014665:Vasodilator Agents / Q000494:pharmacology
D000889:Anti-Arrhythmia Agents; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1; D010456:Peptides, Cyclic; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D044022:Receptor, Endothelin A; D011945:Receptors, Angiotensin; D017466:Receptors, Endothelin; D014665:Vasodilator Agents; D000804:Angiotensin II; D000255:Adenosine Triphosphate; C072247:cyclo(Trp-Asp-Pro-Val-Leu); D005905:Glyburide