Bradley S L, Russell J A
J Appl Physiol Respir Environ Exerc Physiol. 1983 Mar;54(3):693-700. doi: 10.1152/jappl.1983.54.3.693.
The distribution of histamine receptors was examined in isolated trachealis smooth muscle strips and helical strips of large (5 mm) and small (1.5 mm) intrapulmonary airways. All airways contracted in response to histamine, but the sensitivity to this agent was significantly greater in intrapulmonary airways than in trachealis strips. A dose-dependent tachyphylaxis to histamine occurred when airways were exposed repeatedly to 10(-4) M histamine but not to 5 X 10(-6) M histamine. The H1-agonist, 2-methylhistamine, also caused airway contractions, although they were less forceful than those caused by histamine. Both histamine- and 2-methylhistamine-induced contractions were blocked by the H1-antagonist, pyrilamine. The H2-agonists, 4-methylhistamine and dimaprit, as well as histamine in the presence of pyrilamine failed to relax both acetylcholine- and 5-hydroxytryptamine-induced contractions. Moreover, the H2-antagonist, metiamide, had no effect on histamine-induced contractions. We conclude that histamine H1-receptors are present in both extrapulmonary and intrapulmonary airways of the dog and cause contraction when stimulated. In contrast, histamine H2-receptor activity could not be demonstrated in the airways of this species.
在犬离体气管平滑肌条以及大（5毫米）、小（1.5毫米）肺内气道的螺旋条中检测了组胺受体的分布。所有气道对组胺均有收缩反应，但肺内气道对该药物的敏感性显著高于气管条。当气道反复暴露于10⁻⁴M组胺而非5×10⁻⁶M组胺时，会出现对组胺的剂量依赖性快速减敏。H1激动剂2-甲基组胺也会引起气道收缩，尽管其收缩力度小于组胺引起的收缩。组胺和2-甲基组胺诱导的收缩均被H1拮抗剂吡苄明阻断。H2激动剂4-甲基组胺和二甲双胍，以及在吡苄明存在下的组胺，均未能舒张乙酰胆碱和5-羟色胺诱导的收缩。此外，H2拮抗剂甲硫米特对组胺诱导的收缩无影响。我们得出结论，组胺H1受体存在于犬的肺外和肺内气道中，受到刺激时会引起收缩。相比之下，在该物种的气道中未证实有组胺H2受体活性。
