The slices were exposed to different drugs on day one and two after preparation. without affecting pulmonary arteries. Discussion Vasopressin and (nor)epinephrine in combination with 2-inhibition caused pulmonary venoconstriction. If applicable in humans, these treatments would enhance capillary hydrostatic pressures and lung oedema, suggesting their cautious use in left heart failure. Vice versa, the prevention of pulmonary venoconstriction by AT1 receptor antagonists might contribute to their beneficial effects seen in left heart failure. Further, 1-mimetic agents might exacerbate pulmonary hypertension and right ventricular failure by contracting pulmonary arteries, whereas vasopressin might not. Introduction Treatment of acute and chronic heart failure is based on the therapy with cardiovascular agents that aim at improved ventricular contractility, enhanced coronary perfusion and reduced myocardial oxygen consumption. Importantly however, cardiovascular agents interact with the pulmonary vascular bed and thereby also influence myocardial function: First, contraction of pulmonary arteries (PAs) enhances right ventricular afterload and worsens right ventricular failure. Second, contraction of pulmonary veins (PVs) increases pulmonary Anidulafungin capillary pressure and causes hydrostatic pulmonary oedema and deterioration of gas exchange. Thus, it is clinically important how PAs and PVs respond to cardiovascular agents. However, the differential effects of cardiovascular drugs along the pulmonary vascular bed are only incompletely defined. Most previous studies focused on PAs [1]C[5], probably due to their central role in pulmonary hypertension and right ventricular failure. Recently, PVs are receiving growing attention and their relevance in the regulation of total pulmonary vascular resistance is becoming evident [6]. Therefore, and due to completely different responses of PAs and PVs [7], simultaneous studies of both vessels are of great clinical interest; however, they are rare [4]. Further, pulmonary vessels differ from systemic vessels in their response to hypoxia, hypercapnia and acidosis [8], thus results from systemic vessels may not be applicable to the low pressure pulmonary vascular bed. The aim of this study was to investigate the effects of adrenoceptor agonists, vasopressin and angiotensin II on PAs and PVs. We have chosen the model of precision-cut lung slices (PCLS), because it permits simultaneous studies of PAs and PVs. Further, guinea pigs (GPs) were chosen, because previous studies on airway pharmacology suggest that GPs may be a reasonable proxy of human lung tissue [9]. Our results indicate Anidulafungin that GPs’ PAs and PVs respond significantly different to adrenoceptor agonists, vasopressin and angiotension II. These findings Anidulafungin suggest that Anidulafungin differential effects of cardiovascular drugs along the pulmonary vascular tree might influence the success of heart failure therapy. Materials and Methods Guinea pigs (GPs) Female Dunkin Hartley GPs (40050 g) were obtained from Charles River (Sulzfeld, Germany) and held under standard conditions. All animal care and experimental procedures were performed according to the rules of the University Hospital Aachen (Aachen, Germany) and the Directive 2010/63/EU of the Western Parliament. They were authorized by the Landesamt fr Natur, Umwelt und Verbraucherschutz Nordrhein-Westfalen (LANUV, approval-ID: 8.87C51.05.20.10.245). Precision-cut lung slices (PCLS) PCLS from GPs (n?=?39) were prepared as described before [9]. In brief, intraperitoneal anaesthesia was performed with 95 mg kg?1 pentobarbital (Narcoren; Garbsen, Germany) and its depth was monitored by missing reflexes. Later on, the belly was opened and the GP exsanguinated. Further, the trachea was cannulated, the Anidulafungin diaphragm opened and the lungs filled with low melting point agarose (final concentration: 1.5%), containing 1 M isoproterenol. To solidify the agarose, the lungs were covered with snow. The lobes were removed; cells cores prepared and cut into 300 m solid slices having a Krumdieck cells slicer (Alabama Study & Development, Munford, AL, USA). Later on, PCLS were incubated at 37C inside a humid atmosphere in minimal essential medium (MEM), comprising CaCl2 (1.8 mM), MgSO4 (0.8 mM), KCl (5.4 mM), NaCl (116.4 mM), glucose (16.7 mM), NaHCO3 (26.1 mM), Hepes (25.17 mM), sodium pyruvate, amino acids, vitamins and glutamine. To wash out the agarose from your slices, the MEM was changed every half hour during the 1st 2 h and every hour during the next 2 h. For overnight tradition, MEM was completed with penicillin and streptomycin and changed every 24 h. Identification of the vessels, histology Pulmonary MAT1 vessels were identified using the following criteria: PAs accompany the airways and PVs lay aside. After staining with haematoxylin and eosin (HE) PAs.