Biomaterial Database

Involvement of alpha2-adrenoceptors of nucleus tractus solitarius in baroreflex mediated bradycardia. 1982

S Gurtu, and J N Sinha, and K P Bhargava

Microinjections of noradrenaline and clonidine into nucleus tractus solitarius produced dose dependent bradycardia without significant decrease in blood pressure in chloralose anaesthetized cats. Phenylephrine failed to produce any significant alteration of heart rate or blood pressure. Piperoxan microinjection into nucleus tractus solitarius elicited a mild but significant tachycardia and could also block the noradrenaline and clonidine responses. Phenoxybenzamine however neither affected resting heart rate and blood pressure nor antagonized the responses of noradrenaline and clonidine. Guanethidine pretreatment of nucleus tractus solitarius also abolished the clonidine response. Baroreceptor reflex activation induced bradycardia was inhibited by yohimbine or piperoxane injected into the cisterna magna or microinjected bilaterally into the nucleus tractus solitarius. Pretreatment of nucleus tractus solitarius with phenoxybenzamine by either route, did not affect the reflex bradycardia. It is concluded that the alpha-adrenoceptors of nucleus tractus solitarius involved in the decrease in heart rate during baroreceptor activation are alpha2 in nature.

UI	MeSH Term	Description	Entries
D007267	Injections	Introduction of substances into the body using a needle and syringe.	Injectables,Injectable,Injection
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
D010883	Piperoxan	A benzodioxane alpha-adrenergic blocking agent with considerable stimulatory action. It has been used to diagnose PHEOCHROMOCYTOMA and as an antihypertensive agent.	Benodain,Benodaine,Forneau 933,Piperoxane
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
D011941	Receptors, Adrenergic	Cell-surface proteins that bind epinephrine and/or norepinephrine with high affinity and trigger intracellular changes. The two major classes of adrenergic receptors, alpha and beta, were originally discriminated based on their cellular actions but now are distinguished by their relative affinity for characteristic synthetic ligands. Adrenergic receptors may also be classified according to the subtypes of G-proteins with which they bind; this scheme does not respect the alpha-beta distinction.	Adrenergic Receptors,Adrenoceptor,Adrenoceptors,Norepinephrine Receptor,Receptors, Epinephrine,Receptors, Norepinephrine,Adrenergic Receptor,Epinephrine Receptors,Norepinephrine Receptors,Receptor, Adrenergic,Receptor, Norepinephrine
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.
D001794	Blood Pressure	PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.	Systolic Pressure,Diastolic Pressure,Pulse Pressure,Pressure, Blood,Pressure, Diastolic,Pressure, Pulse,Pressure, Systolic,Pressures, Systolic