RESUMEN
The isolated mesenteric vascular-intestinal loop preparation has been shown to be an important model of resistance vessel hemodynamics reflective of both physiological and pathological conditions. The present experiments were performed to characterize the isolated rat mesenteric vascular-intestinal loop preparations. The mesenteric vasculature with intestine was perfused with modified Krebs-Ringer bicarbonate solution at a constant flow of 5 mL/min. To examine spontaneous norepinephrine overflow, the perfusate and superfusate were collected for 4-min periods from 36 to 60 min after the start of the perfusion. The norepinephrine overflow from the mesenteric vasculature was also determined in response to field stimulation (FS). Basal spontaneous endogenous norepinephrine overflow was relatively constant. The spontaneous norepinephrine overflow was increased by guanethidine (10(-5) M) but was not influenced by tetrodotoxin (3 x 10(-7) M), cocaine (10(-6) M), or prazosin (10(-6) M) treatment. Field stimulation (4-12 Hz) caused frequency-dependent pressor responses and increases in norepinephrine overflow. When norepinephrine overflow was expressed as amount/stimulus (picogram/stimulus), it was frequency independent. The pressor responses to FS were abolished by guanethidine (10(-5) M), tetrodotoxin (3 x 10(-7) M), and prazosin (3 x 10(-8) M). Prazosin at 10(-6) M significantly augmented the FS-induced endogenous norepinephrine overflow. Thus, these results indicate that the isolated rat mesenteric vascular-intestinal loop preparation is an excellent model for demonstrating resistance changes in isolated vascular beds while simultaneously measuring endogenous catecholamine overflow.
Asunto(s)
Intestinos/irrigación sanguínea , Arterias Mesentéricas/fisiología , Venas Mesentéricas/fisiología , Animales , Presión Sanguínea , Depresores del Sistema Nervioso Central/farmacología , Cromatografía Líquida de Alta Presión , Estimulación Eléctrica , Masculino , Modelos Biológicos , Norepinefrina/fisiología , Perfusión , Prazosina/farmacología , Ratas , Ratas Endogámicas , Tetrodotoxina/farmacologíaRESUMEN
A 47 year-old male was admitted to Miyazaki Medical college Hospital for further evaluation of an abdominal mass in the left upper quadrant. Abdominal ultrasound (US) and abdominal computed tomography (CT) showed two cystic masses in the mesenterium, which were suspected to be hematomas, but were not related to the pancreas, kidney or spleen. Superior mesenteric artery angiography and gallium (GA)-scintigraphy showed no definite findings. The patient underwent laparotomy on a suspicion of mesenteric hematoma. Two 4 x 3 x 3 cm soft tumors were found in the small intestinal mesenterium. These masses were histopathologically hematomas and surrounded by thick collagenous granulation tissue. The patient had no recent history of abdominal trauma, taking drugs capable of producing bleeding tendency, and/or vascular disease. The case was diagnosed as spontaneous mesenteric hematoma.
Asunto(s)
Hematoma/epidemiología , Hemoperitoneo/epidemiología , Hematoma/diagnóstico , Hemoperitoneo/diagnóstico , Humanos , Japón/epidemiología , Masculino , Persona de Mediana EdadRESUMEN
In the isolated guinea pig ileum, the effects of I-ephedrine on the twitch response to field stimulation were investigated in the presence of propranolol. Ephedrine and clonidine inhibited the twitch response but not the contraction to exogenous acetylcholine. The inhibitory effect of clonidine was significantly diminished by yohimbine pretreatment. However, the inhibitory effect of ephedrine was not influenced by yohimbine, sulpiride or 6-hydroxydopamine (6-OHDA) pretreatment. Most of this action of ephedrine appeared to be cholinergic prejunctional in nature, but unrelated to activation of prejunctional alpha 2-adrenoceptors and dopamine sensitive receptors on the cholinergic nerves in this preparation.