Biomaterial Database

Excitatory amino acid receptors in the nucleus tractus solitarius mediate the responses to the stimulation of cardio-pulmonary vagal afferent C fiber endings. 1993

A Vardhan, and A Kachroo, and H N Sapru

Section of Neurological Surgery, UMDNJ-New Jersey Medical School, Newark 07103.

Stimulation of cardio-pulmonary vagal afferent C fiber endings by right atrial injections of phenylbiguanide (PBG, 40 micrograms/kg) elicited apnea, bradycardia and hypotension. These responses were abolished by bilateral vagotomy low in the neck. Stimulation of neurons in a specific nucleus tractus solitarius site (0.5 mm rostral, 0.5 mm lateral and 0.5 mm deep with reference to the calamus scriptorius) by injections of L-glutamate produced responses similar to those following the stimulation of cardio-pulmonary vagal afferent C fiber endings by PBG. Inhibition of neurons in this NTS site by injections of muscimol abolished the responses to PBG. Specific blockade of NMDA receptors by microinjections of AP-7 (100 pmol) or non-NMDA receptors (KA and AMPA) by injections of DNQX (10-25 pmol) into this NTS site did not block the responses to PBG. Microinjections of kynurenic acid (1-4 nmol) into this NTS site blocked the responses to right atrial injections of PBG. These results indicate that: (1) blockade of either NMDA receptors or non-NMDA receptors (KA and AMPA) alone in the above-mentioned NTS site does not abolish the responses to the stimulation of cardio-pulmonary vagal afferent C fiber endings; (2) it is necessary to block NMDA as well as non-NMDA receptors in this NTS site for abolishing the responses to the stimulation of these nerve endings.

UI	MeSH Term	Description	Entries
D008168	Lung	Either of the pair of organs occupying the cavity of the thorax that effect the aeration of the blood.	Lungs
D008297	Male		Males
D008845	Microinjections	The injection of very small amounts of fluid, often with the aid of a microscope and microsyringes.	Microinjection
D009118	Muscimol	A neurotoxic isoxazole isolated from species of AMANITA. It is obtained by decarboxylation of IBOTENIC ACID. Muscimol is a potent agonist of GABA-A RECEPTORS and is used mainly as an experimental tool in animal and tissue studies.	Agarin,Pantherine
D009411	Nerve Endings	Branch-like terminations of NERVE FIBERS, sensory or motor NEURONS. Endings of sensory neurons are the beginnings of afferent pathway to the CENTRAL NERVOUS SYSTEM. Endings of motor neurons are the terminals of axons at the muscle cells. Nerve endings which release neurotransmitters are called PRESYNAPTIC TERMINALS.	Ending, Nerve,Endings, Nerve,Nerve Ending
D009412	Nerve Fibers	Slender processes of NEURONS, including the AXONS and their glial envelopes (MYELIN SHEATH). Nerve fibers conduct nerve impulses to and from the CENTRAL NERVOUS SYSTEM.	Cerebellar Mossy Fibers,Mossy Fibers, Cerebellar,Cerebellar Mossy Fiber,Mossy Fiber, Cerebellar,Nerve Fiber
D011810	Quinoxalines		Quinoxaline
D006321	Heart	The hollow, muscular organ that maintains the circulation of the blood.	Hearts
D000344	Afferent Pathways	Nerve structures through which impulses are conducted from a peripheral part toward a nerve center.	Afferent Pathway,Pathway, Afferent,Pathways, Afferent
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia