Role of endothelium and nitric oxide in histamine‐induced responses in human cranial arteries and detection of mRNA encoding H₁‐ and H₂‐receptors by RT‐PCR

Abstract

1 Histamine induces relaxation of human cranial arteries. Studies have revealed that the relaxant histamine H 1 -receptor predominates in human cerebral and the H 2 -receptor in temporal arteries, while H 1 -and H 2 -receptors are of equal importance in the middle meningeal artery. The purpose of the present study was to examine the role of the endothelium and nitric oxide in histamine-induced responses and to show the presence of mRNA encoding H 1 -and H 2 -receptors in human cranial arteries. 2 Electrophoresis of polymerase chain reaction (PCR) products from human cerebral, middle meningeal and temporal arteries, demonstrated products corresponding to mRNA encoding both H 1 -and H 2 -receptors in arteries with and without endothelium. The ampli®ed PCR products were sequenced and showed 100% homology with the published sequences of these histamine receptors. 3 A sensitive in vitro system was used to study vasomotor responses to histamine. In precontracted cerebral, middle meningeal and temporal arteries with and without endothelium, histamine caused a concentration-dependent relaxation with I max values between 87% and 81% and pIC 50 values between 8.14 and 7.15. In arteries without endothelium the histamine-induced relaxation was signi®cantly less potent (I max values between 87% and 66% and pIC 50 values between 7.01 and 6.67) than in cranial arteries with an intact endothelium. 4 The addition of histamine to arteries without endothelium and pretreated with the histamine H 2 -antagonist, cimetidine (10 75 M), caused a concentration-dependent contraction of the cranial arteries with E max values between 86% and 29% and pEC 50 values between 7.53 and 6.77. This contraction was blocked by the histamine H 1 -receptor antagonist, mepyramine (10 77 M), and even turned into a relaxation with I max values between 84% and 14% and pIC 50 values between 7.42 and 5.86. 5 The nitric oxide synthase inhibitor N G -nitro-L-arginine methyl ester (L-NAME, 3610 75 M) signi®cantly inhibited the relaxant response to histamine in cerebral and temporal arteries (pIC 50 values between 7.43 and 7.13). The combined treatment with L-NAME (3610 75 M) and cimetidine (10 75 M) caused a further displacement of the concentration-response curve (pIC 50 values between 7.14 and 6.57) and decreased the maximum relaxant responses in all three cranial arteries (I max values between 62% and 39%). 6 In conclusion, this is the ®rst study which show mRNA encoding histamine H 1 -and H 2 -receptors in human cranial arteries. The results indicate that histamine-induced relaxation of human cranial arteries is partially mediated via an endothelial H 1 -receptor coupled to the production of nitric oxide and partially via a H 2 -receptor associated with the smooth muscle cells. In addition, there is evidence for a contractile H 1 -receptor in the smooth muscle cells in these arteries.

Activation of hexosamine pathway impairs nitric oxide (NO)-dependent arteriolar dilations by increased protein O-GlcNAcylation

“…Histamine has been shown to cause the release of NO in several vascular beds (Weksler et al, 1978). The histamine-induced relaxation is endothelium-dependent and it is mediated by endothelial H 1 receptors (Jansen-Olesen et al, 1997; Toda, 1990). Histamine was chosen to examine the effect of high glucose on eNOS activity because we have shown previously that NO synthase inhibitor, L-NAME had a more pronounced effect on histamine-induced dilation in skeletal muscle arterioles, which suggests NO as an important mediator of the histamine response (Erdei et al, 2006).…”

Histamine regulates cytokine production in maturing dendritic cells, resulting in altered T cell polarization

“…Total RNA was isolated from iDCs using TRIzol (Life Technologies Inc., Rockville, Maryland, USA) according to the manufacturer's instructions. cDNA was synthesized from 2 µg of total RNA using a SuperScript II reverse transcriptase extension kit (Life Technologies Inc.), and amplified using 200 ng of cDNA, with primers complementary to the published sequences of the three histamine receptors, H1, H2, and H3 (29), or GAPDH (Clontech Laboratories Inc., Palo Alto, California, USA), and a Taq polymerase PCR kit (Life Technologies Inc.). Thirty-five cycles were per-formed (1 minute at 94°C for denaturation, 1 minute at 55°C for annealing, and 1 minute at 72°C for extension).…”

Diadenosine Polyphosphates Are Largely Ineffective as Agonists at Natively Expressed P2Y₁ and P2Y₂ Receptors on Cultured Human Saphenous Vein Endothelial Cells

“…Primers for P2Y 1 , P2Y 2 , P2Y 4 and P2Y 6 receptors were as described by Maier et al [16]and amplified specific products from HSVEC genomic DNA of 237, 344, 411 and 453 bp, respectively. Histamine H 1 receptor primers were as described by Jansen-Olesen et al [17]and were used as positive controls to monitor reaction conditions for all P2Y receptor primers. RT-PCR reactions were performed in a total volume of 25 µl, containing 0.2 m M dNTP mix, 12 pmol of each primer and 5 U Taq polymerase (Boehringer).…”