Cará A M, Lopes-Martins R A, Antunes E, Nahoum C R, De Nucci G
Discipline of Urology, Faculty of Medical Sciences, UNICAMP, Campinas, Brazil.
Br J Urol. 1995 Feb;75(2):220-4. doi: 10.1111/j.1464-410x.1995.tb07315.x.
To investigate the relaxant action of histamine on human corpus cavernosum in vitro and the erectile response caused by the intracavernous injection of histamine in patients with psychogenic impotence.
Human corpus cavernosum (HCC) tissue was cut into strips of approximately 2 cm and suspended in a cascade bioassay. The strips were then superfused with oxygenated and warmed Krebs solution and precontracted with noradrenaline (3 microM). Glyceryl trinitrate, acetylcholine and histamine were injected as a single bolus in the absence or in the presence of mepyramine and cimetidine. For the in vivo studies, histamine (30-60 micrograms) was injected intracavernously as a single bolus into the right corpus cavernosum 1 cm from the balamo-preputial sulcus. Similar protocols were carried out for papaverine (50 mg). The erectile response was divided into four grades: no response, tumescence, partial and full erection.
In vitro studies demonstrated that histamine (3-100 micrograms) caused dose-dependent relaxation of the HCC strips which was significantly inhibited by cimetidine (5-10 microM). The histamine H1 receptor antagonist mepyramine (1 microM) potentiated histamine-induced relaxation. The co-infusion of both mepyramine and cimetidine did not abolish histamine-induced relaxation. When injected intracavernously in humans, histamine (30 micrograms) caused full erection in 13% of the patients, whereas 87% had partial erection or tumescence. A higher dose of histamine (60 micrograms) caused full erection in 26% of the patients and 74% had partial erection or tumescence. Papaverine induced full erection in the majority of patients (66%). In contrast to papaverine, the duration of erection induced by histamine was markedly shorter (mean 200 and 6.5 min, respectively). The penile erections induced by papaverine were associated with complications such as pain, haematoma and priapism. Histamine did not induce any complications. Treatment of eight male patients with psychogenic impotence with the histamine H1 receptor antagonist astemizol (10 mg orally once daily for 1 week) did not affect histamine-induced erectile responses.
These results indicate that histamine may play a role in human penile erection. The erection-promoting action of histamine is probably due to H2 receptor activation, although another histamine receptor, possibly H3, also seems to be involved. This study suggests that histamine could be a valuable tool in the diagnosis of erectile dysfunction.
研究组胺对体外人阴茎海绵体的舒张作用以及组胺海绵体内注射对心因性阳痿患者引起的勃起反应。
将人阴茎海绵体（HCC）组织切成约2厘米长的条带，悬挂于级联生物测定仪中。然后用充氧且温热的克雷布斯溶液对条带进行灌流，并用去甲肾上腺素（3微摩尔）使其预收缩。在不存在或存在美吡拉敏和西咪替丁的情况下，单次推注硝酸甘油、乙酰胆碱和组胺。对于体内研究，将组胺（30 - 60微克）作为单次推注经海绵体注射到距龟头-包皮沟1厘米处的右侧阴茎海绵体内。对罂粟碱（50毫克）采用类似方案。勃起反应分为四个等级：无反应、肿胀、部分勃起和完全勃起。
体外研究表明，组胺（3 - 100微克）引起HCC条带剂量依赖性舒张，西咪替丁（5 - 10微摩尔）可显著抑制该舒张作用。组胺H1受体拮抗剂美吡拉敏（1微摩尔）增强组胺诱导的舒张作用。美吡拉敏和西咪替丁共同灌流并未消除组胺诱导的舒张作用。在人体海绵体内注射时，组胺（30微克）使13%的患者完全勃起，而87%的患者有部分勃起或肿胀。更高剂量的组胺（60微克）使26%的患者完全勃起，74%的患者有部分勃起或肿胀。罂粟碱使大多数患者（66%）完全勃起。与罂粟碱不同，组胺诱导的勃起持续时间明显较短（分别平均为200分钟和6.5分钟）。罂粟碱诱导的阴茎勃起伴有疼痛、血肿和阴茎异常勃起等并发症。组胺未诱发任何并发症。用组胺H1受体拮抗剂阿司咪唑（每天口服10毫克，共1周）治疗8例心因性阳痿男性患者，并未影响组胺诱导的勃起反应。
这些结果表明组胺可能在人类阴茎勃起中起作用。组胺的促勃起作用可能归因于H2受体激活，尽管另一种组胺受体，可能是H3受体，似乎也参与其中。本研究提示组胺可能是诊断勃起功能障碍的一种有价值的工具。
