Effects of substance P on cardiovascular regulation in the rabbit

• Published in: Journal of the autonomic nervous system Vol. 51; no. 2; pp. 143 - 152
• Main Authors: Martini, Fabienne, Reynaud, Jean-Claude, Puizillout, Jean-Jacques
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 09.02.1995; Elsevier Science
• Subjects: Animals; Aortic nerve; Baroceptor reflex; Baroreflex - drug effects; Biological and medical sciences; Blood Pressure - drug effects; Cardiovascular System - drug effects; Dorsal vagal nucleus; Electric Stimulation; Fundamental and applied biological sciences. Psychology; Heart Rate - drug effects; Injections, Intra-Arterial; Injections, Intraventricular; Male; Motor control and motor pathways. Reflexes. Control centers of vegetative functions. Vestibular system and equilibration; NK 1-receptor agonist; NK 1-receptor antagonist; Piperidines - pharmacology; Quinuclidines - pharmacology; Rabbits; Substance P; Substance P - analogs & derivatives; Substance P - pharmacology; Vertebral Artery; Vertebrates: nervous system and sense organs; NK 1-receptor antagonist; Aortic nerve; Substance P; NK 1-receptor agonist; Dorsal vagal nucleus; Baroceptor reflex; Cardiovascular control; NK1 receptor; Rabbit; Motor pneumogastric nucleus; Lagomorpha; Neuropeptide; Vertebrata; Mammalia; Autonomic nervous system; Baroreflex; Blood pressure; Hemodynamics; Tachykinin; Parasympathetic nervous system
• ISSN: 0165-1838; 1872-7476
• DOI: 10.1016/0165-1838(94)00126-5

The effect of substance P on blood pressure and aortic reflex was investigated in rabbits. Microinjections of substance P and Sar 9, Met(O2) 11-SP (a selective NK 1-receptor agonist) into the floor of the fourth ventricle led to a dose-dependent increase of blood pressure and a sharp enhancement of the baroreflex. These effects were abolished by pretreatment with SR 140333 (a selective NK 1-receptor antagonist). Intraventricular injection of the antagonist alone significantly decreased the amplitude of the aortic reflex. After bivabotomy, the amplitude of the parasympathetic component of the baroreflex decreased dramatically and substance P injections were no longer effective. Our results demonstrate that substance P activation of NK 1 receptors plays a major role in the modulation of the parasympathetic component of the baroceptor reflex.