Monocrotaline: A pyrrolizidine alkaloid and a toxic plant constituent that poisons livestock and humans through the ingestion of contaminated grains and other foods. The alkaloid causes pulmonary artery hypertension, right ventricular hypertrophy, and pathological changes in the pulmonary vasculature. Significant attenuation of the cardiopulmonary changes are noted after oral magnesium treatment.Pyrrolizidine Alkaloids: A group of ALKALOIDS, characterized by a nitrogen-containing necine, occurring mainly in plants of the BORAGINACEAE; COMPOSITAE; and LEGUMINOSAE plant families. They can be activated in the liver by hydrolysis of the ester and desaturation of the necine base to reactive electrophilic pyrrolic CYTOTOXINS.Hypertrophy, Right Ventricular: Enlargement of the RIGHT VENTRICLE of the heart. This increase in ventricular mass is often attributed to PULMONARY HYPERTENSION and is a contributor to cardiovascular morbidity and mortality.Poisons: Substances which, when ingested, inhaled, or absorbed, or when applied to, injected into, or developed within the body in relatively small amounts may, by their chemical action, cause damage to structure or disturbance of function. (From Dorland, 27th ed)Hypertension, Pulmonary: Increased VASCULAR RESISTANCE in the PULMONARY CIRCULATION, usually secondary to HEART DISEASES or LUNG DISEASES.Senecio: A species of toxic plants of the Compositae. The poisonous compounds are alkaloids which cause cattle diseases, neoplasms, and liver damage and are used to produce cancers in experimental animals.Pulmonary Artery: The short wide vessel arising from the conus arteriosus of the right ventricle and conveying unaerated blood to the lungs.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Bone Morphogenetic Protein Receptors, Type II: A subtype of bone morphogenetic protein receptors with low affinity for BONE MORPHOGENETIC PROTEINS. They are constitutively active PROTEIN-SERINE-THREONINE KINASES that can interact with and phosphorylate TYPE I BONE MORPHOGENETIC PROTEIN RECEPTORS.Lung: Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.Crotalaria: A plant genus of the family FABACEAE that contains crotalarin.Disease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.Pulmonary Circulation: The circulation of the BLOOD through the LUNGS.Pulmonary Heart Disease: Hypertrophy and dilation of the RIGHT VENTRICLE of the heart that is caused by PULMONARY HYPERTENSION. This condition is often associated with pulmonary parenchymal or vascular diseases, such as CHRONIC OBSTRUCTIVE PULMONARY DISEASE and PULMONARY EMBOLISM.Ventricular Dysfunction, Right: A condition in which the RIGHT VENTRICLE of the heart was functionally impaired. This condition usually leads to HEART FAILURE or MYOCARDIAL INFARCTION, and other cardiovascular complications. Diagnosis is made by measuring the diminished ejection fraction and a depressed level of motility of the right ventricular wall.Rats, Wistar: A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.Ventricular Pressure: The pressure within a CARDIAC VENTRICLE. Ventricular pressure waveforms can be measured in the beating heart by catheterization or estimated using imaging techniques (e.g., DOPPLER ECHOCARDIOGRAPHY). The information is useful in evaluating the function of the MYOCARDIUM; CARDIAC VALVES; and PERICARDIUM, particularly with simultaneous measurement of other (e.g., aortic or atrial) pressures.Hemodynamics: The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.Organ Size: The measurement of an organ in volume, mass, or heaviness.Ventricular Function, Right: The hemodynamic and electrophysiological action of the right HEART VENTRICLE.