Biomaterial Database

Role of alpha-adrenergic mechanisms on responses to area postrema stimulation and circulating vasopressin. 1993

E M Hasser, and V S Bishop

Department of Veterinary Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia 65211.

This study evaluated the role of catecholamines in the nucleus tractus solitarius (NTS) on the inhibition of renal sympathetic nerve activity (RSNA) due to direct electrical stimulation of the area postrema. In addition, the effects of catecholaminergic mechanisms in the NTS on the ability of circulating arginine vasopressin (AVP) to modulate arterial baroreflex control of RSNA were evaluated. Electrical stimulation of the area postrema (15 microA, 0.3 ms, 5-80 Hz) produced progressive decreases in RSNA. Responses to area postrema activation were not altered by microinjection of the alpha 1-adrenergic antagonist, prazosin, or vehicle bilaterally into the NTS. Microinjection of the alpha 2-antagonist, yohimbine (4 injections of 20-40 nl, 1 ng/nl), unilaterally into the NTS significantly attenuated the RSNA response to area postrema stimulation. Bilateral injection of yohimbine into the NTS abolished the response to area postrema activation (P < 0.05). Baroreflex inhibition of RSNA was significantly greater during infusion of AVP than during infusion of phenylephrine (slopes = -5.18 +/- 0.39 and -2.64 +/- 0.27 for AVP and phenylephrine, respectively). Microinjection of yohimbine bilaterally into the NTS did not alter the slope of baroreflex control of RSNA for phenylephrine but normalized the slope for AVP (-2.85 +/- 0.54) to that of phenylephrine. Data are consistent with the hypothesis that AVP effects on baroreflex inhibition of RSNA and area postrema-mediated inhibition of RSNA require alpha 2-adrenergic signaling within the NTS.

UI	MeSH Term	Description	Entries
D007668	Kidney	Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.	Kidneys
D008297	Male		Males
D008526	Medulla Oblongata	The lower portion of the BRAIN STEM. It is inferior to the PONS and anterior to the CEREBELLUM. Medulla oblongata serves as a relay station between the brain and the spinal cord, and contains centers for regulating respiratory, vasomotor, cardiac, and reflex activities.	Accessory Cuneate Nucleus,Ambiguous Nucleus,Arcuate Nucleus of the Medulla,Arcuate Nucleus-1,External Cuneate Nucleus,Lateral Cuneate Nucleus,Nucleus Ambiguus,Ambiguus, Nucleus,Arcuate Nucleus 1,Arcuate Nucleus-1s,Cuneate Nucleus, Accessory,Cuneate Nucleus, External,Cuneate Nucleus, Lateral,Medulla Oblongatas,Nucleus, Accessory Cuneate,Nucleus, Ambiguous,Nucleus, External Cuneate,Nucleus, Lateral Cuneate
D008845	Microinjections	The injection of very small amounts of fluid, often with the aid of a microscope and microsyringes.	Microinjection
D011311	Pressoreceptors	Receptors in the vascular system, particularly the aorta and carotid sinus, which are sensitive to stretch of the vessel walls.	Baroreceptors,Receptors, Stretch, Arterial,Receptors, Stretch, Vascular,Stretch Receptors, Arterial,Stretch Receptors, Vascular,Arterial Stretch Receptor,Arterial Stretch Receptors,Baroreceptor,Pressoreceptor,Receptor, Arterial Stretch,Receptor, Vascular Stretch,Receptors, Arterial Stretch,Receptors, Vascular Stretch,Stretch Receptor, Arterial,Stretch Receptor, Vascular,Vascular Stretch Receptor,Vascular Stretch Receptors
D011817	Rabbits	A burrowing plant-eating mammal with hind limbs that are longer than its fore limbs. It belongs to the family Leporidae of the order Lagomorpha, and in contrast to hares, possesses 22 instead of 24 pairs of chromosomes.	Belgian Hare,New Zealand Rabbit,New Zealand Rabbits,New Zealand White Rabbit,Rabbit,Rabbit, Domestic,Chinchilla Rabbits,NZW Rabbits,New Zealand White Rabbits,Oryctolagus cuniculus,Chinchilla Rabbit,Domestic Rabbit,Domestic Rabbits,Hare, Belgian,NZW Rabbit,Rabbit, Chinchilla,Rabbit, NZW,Rabbit, New Zealand,Rabbits, Chinchilla,Rabbits, Domestic,Rabbits, NZW,Rabbits, New Zealand,Zealand Rabbit, New,Zealand Rabbits, New,cuniculus, Oryctolagus
D011942	Receptors, Adrenergic, alpha	One of the two major pharmacological subdivisions of adrenergic receptors that were originally defined by the relative potencies of various adrenergic compounds. The alpha receptors were initially described as excitatory receptors that post-junctionally stimulate SMOOTH MUSCLE contraction. However, further analysis has revealed a more complex picture involving several alpha receptor subtypes and their involvement in feedback regulation.	Adrenergic alpha-Receptor,Adrenergic alpha-Receptors,Receptors, alpha-Adrenergic,alpha-Adrenergic Receptor,alpha-Adrenergic Receptors,Receptor, Adrenergic, alpha,Adrenergic alpha Receptor,Adrenergic alpha Receptors,Receptor, alpha-Adrenergic,Receptors, alpha Adrenergic,alpha Adrenergic Receptor,alpha Adrenergic Receptors,alpha-Receptor, Adrenergic,alpha-Receptors, Adrenergic
D012018	Reflex	An involuntary movement or exercise of function in a part, excited in response to a stimulus applied to the periphery and transmitted to the brain or spinal cord.
D002552	Cerebral Ventricles	Four CSF-filled (see CEREBROSPINAL FLUID) cavities within the cerebral hemispheres (LATERAL VENTRICLES), in the midline (THIRD VENTRICLE) and within the PONS and MEDULLA OBLONGATA (FOURTH VENTRICLE).	Foramen of Monro,Cerebral Ventricular System,Cerebral Ventricle,Cerebral Ventricular Systems,Monro Foramen,System, Cerebral Ventricular,Systems, Cerebral Ventricular,Ventricle, Cerebral,Ventricles, Cerebral,Ventricular System, Cerebral,Ventricular Systems, Cerebral
D004558	Electric Stimulation	Use of electric potential or currents to elicit biological responses.	Stimulation, Electric,Electrical Stimulation,Electric Stimulations,Electrical Stimulations,Stimulation, Electrical,Stimulations, Electric,Stimulations, Electrical