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Histamine decreases myogenic tone in rat cerebral arteries by H2-receptor-mediated KV channel activation, independent of endothelium and cyclic AMP.
Eur J Pharmacol. 2006 Oct 10; 547(1-3):116-24.EJ

Abstract

The effect of histamine on the pressure-induced constriction was characterized in rat cerebral arteries and mechanisms were investigated. Rat cerebral arteries were pressurized to 70 mm Hg in an arteriograph and the effect of histamine on myogenic tone was studied. Histamine and amthamine, a selective histamine H(2)-receptor agonist, concentration-dependently decreased myogenic tone, which was unchanged in the absence of endothelium. 2-(2-aminoethyl) pyridine, a selective histamine H(1)-receptor agonist, produced concentration-dependent constriction of arteries that was significantly increased in the absence of endothelium. Imetit, a selective histamine H(3)-receptor agonist, has no effect on myogenic tone. The dilation to histamine was antagonized by tiotidine, a selective antagonist of histamine H(2)-receptor subtype, giving a pK(B) of 7.86 that was not altered in the absence of endothelium. The histamine-mediated dilation was significantly antagonized by NF 449, a reversible inhibitor of Gs-protein activation but was not affected by ODQ and SQ 22536. Dilations to histamine and amthamine were accompanied by a decrease in arterial wall calcium measured by fura-2 ratios. The dilation to histamine was significantly reduced by partial depolarization of smooth muscle by 25 mM KCl (control 91+/-5%, 25 mM KCl 53+/-5%, P<0.002) and was not observed in the presence of strongly depolarizing 60 mM KCl. The histamine dilation was not affected by iberiotoxin, barium chloride and glibenclamide but was strongly antagonized by 4-aminopyridine (0.3 mM) and tetraethylammonium chloride (10 mM) (pEC(50): control: 5.6+/-0.1, 4-aminopyridine: 4.1+/-0.1 (P<0.001); tetraethylammonium chloride: 3.2+/-0.2 (P<0.0001)). These results suggest that histamine-mediated reversal of myogenic tone in rat cerebral arteries is endothelium-independent, mediated by histamine H(2)-receptor subtype with no involvement of guanylyl cyclase or adenylyl cyclase activation and most likely involves activation of K(V) potassium channels.

Authors+Show Affiliations

Department of Pharmacology and Therapeutics, University of Florida, Gainesville, FL 32610, USA. yjarajap@wfubmc.edu <yjarajap@wfubmc.edu>No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

16920098

Citation

Jarajapu, Yagna P R., et al. "Histamine Decreases Myogenic Tone in Rat Cerebral Arteries By H2-receptor-mediated KV Channel Activation, Independent of Endothelium and Cyclic AMP." European Journal of Pharmacology, vol. 547, no. 1-3, 2006, pp. 116-24.
Jarajapu YP, Oomen C, Uteshev VV, et al. Histamine decreases myogenic tone in rat cerebral arteries by H2-receptor-mediated KV channel activation, independent of endothelium and cyclic AMP. Eur J Pharmacol. 2006;547(1-3):116-24.
Jarajapu, Y. P., Oomen, C., Uteshev, V. V., & Knot, H. J. (2006). Histamine decreases myogenic tone in rat cerebral arteries by H2-receptor-mediated KV channel activation, independent of endothelium and cyclic AMP. European Journal of Pharmacology, 547(1-3), 116-24.
Jarajapu YP, et al. Histamine Decreases Myogenic Tone in Rat Cerebral Arteries By H2-receptor-mediated KV Channel Activation, Independent of Endothelium and Cyclic AMP. Eur J Pharmacol. 2006 Oct 10;547(1-3):116-24. PubMed PMID: 16920098.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Histamine decreases myogenic tone in rat cerebral arteries by H2-receptor-mediated KV channel activation, independent of endothelium and cyclic AMP. AU - Jarajapu,Yagna P R, AU - Oomen,Charlotte, AU - Uteshev,Victor V, AU - Knot,Harm J, Y1 - 2006/07/27/ PY - 2006/05/10/received PY - 2006/07/19/revised PY - 2006/07/20/accepted PY - 2006/8/22/pubmed PY - 2006/12/16/medline PY - 2006/8/22/entrez SP - 116 EP - 24 JF - European journal of pharmacology JO - Eur J Pharmacol VL - 547 IS - 1-3 N2 - The effect of histamine on the pressure-induced constriction was characterized in rat cerebral arteries and mechanisms were investigated. Rat cerebral arteries were pressurized to 70 mm Hg in an arteriograph and the effect of histamine on myogenic tone was studied. Histamine and amthamine, a selective histamine H(2)-receptor agonist, concentration-dependently decreased myogenic tone, which was unchanged in the absence of endothelium. 2-(2-aminoethyl) pyridine, a selective histamine H(1)-receptor agonist, produced concentration-dependent constriction of arteries that was significantly increased in the absence of endothelium. Imetit, a selective histamine H(3)-receptor agonist, has no effect on myogenic tone. The dilation to histamine was antagonized by tiotidine, a selective antagonist of histamine H(2)-receptor subtype, giving a pK(B) of 7.86 that was not altered in the absence of endothelium. The histamine-mediated dilation was significantly antagonized by NF 449, a reversible inhibitor of Gs-protein activation but was not affected by ODQ and SQ 22536. Dilations to histamine and amthamine were accompanied by a decrease in arterial wall calcium measured by fura-2 ratios. The dilation to histamine was significantly reduced by partial depolarization of smooth muscle by 25 mM KCl (control 91+/-5%, 25 mM KCl 53+/-5%, P<0.002) and was not observed in the presence of strongly depolarizing 60 mM KCl. The histamine dilation was not affected by iberiotoxin, barium chloride and glibenclamide but was strongly antagonized by 4-aminopyridine (0.3 mM) and tetraethylammonium chloride (10 mM) (pEC(50): control: 5.6+/-0.1, 4-aminopyridine: 4.1+/-0.1 (P<0.001); tetraethylammonium chloride: 3.2+/-0.2 (P<0.0001)). These results suggest that histamine-mediated reversal of myogenic tone in rat cerebral arteries is endothelium-independent, mediated by histamine H(2)-receptor subtype with no involvement of guanylyl cyclase or adenylyl cyclase activation and most likely involves activation of K(V) potassium channels. SN - 0014-2999 UR - https://www.unboundmedicine.com/medline/citation/16920098/Histamine_decreases_myogenic_tone_in_rat_cerebral_arteries_by_H2_receptor_mediated_KV_channel_activation_independent_of_endothelium_and_cyclic_AMP_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0014-2999(06)00784-9 DB - PRIME DP - Unbound Medicine ER -