Biomaterial Database

Neurochemical interactions in the parabrachial nucleus mediating visceral inputs to visceral thalamic neurons. 1995

T M Saleh, and D F Cechetto

Robarts Research Institute, University of Western Ontario, London, Canada.

Previously we demonstrated that glutamatergic and noradrenergic receptors mediate the relay of visceral information through the parabrachial nucleus (PBN) and that calcitonin gene-related peptide (CGRP), substance P (SP), somatostatin (SOM), neurotensin (NT), and cholecystokinin (CCK) may modulate these responses. The interactions of these neurotransmitters and neuropeptides were examined in male Wistar rats (17) that were anesthetized with chloral hydrate and ventilated and in which blood pressure and heart rate were continuously monitored. The left cervical vagus nerve was stimulated at submaximal current intensities to elicit changes in single and multiunit activity of visceral thalamic neurons (VTNs). Peristimulus-time and continuous-time histograms of VTN activity were made before and after 200-nl injections of peptides, neurotransmitter agonists or antagonists, or artificial cerebrospinal fluid into the PBN. Combined injection of CGRP and SP into the PBN produced a synergistic inhibition of spontaneous VTN activity and the vagally evoked VTN response. Combined injection of NT and phenylephrine (PE) into the PBN produced only an additive increase in the spontaneous activity of VTNs. Prior administration of SOM in the PBN blocked the excitatory action of an alpha-adrenergic agonist (phenylephrine) injection on the spontaneous activity of VTNs, whereas CGRP, SP, or CCK had no effect on the alpha-agonist-induced response. Prior injection of an alpha-adrenergic antagonist (phentolamine) prevented the excitatory effect of NT in the PBN. Injection of CGRP, SP, NT, or CCK into the PBN did not change the response of VTNs to application of glutamate. These results suggest mechanisms for peptide interaction with primary neurotransmitters in the PBN and indicate whether the neuropeptides are acting before the primary neurotransmitter synapse or postsynaptically.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D009434	Neural Pathways	Neural tracts connecting one part of the nervous system with another.	Neural Interconnections,Interconnection, Neural,Interconnections, Neural,Neural Interconnection,Neural Pathway,Pathway, Neural,Pathways, Neural
D009435	Synaptic Transmission	The communication from a NEURON to a target (neuron, muscle, or secretory cell) across a SYNAPSE. In chemical synaptic transmission, the presynaptic neuron releases a NEUROTRANSMITTER that diffuses across the synaptic cleft and binds to specific synaptic receptors, activating them. The activated receptors modulate specific ion channels and/or second-messenger systems in the postsynaptic cell. In electrical synaptic transmission, electrical signals are communicated as an ionic current flow across ELECTRICAL SYNAPSES.	Neural Transmission,Neurotransmission,Transmission, Neural,Transmission, Synaptic
D009496	Neurotensin	A biologically active tridecapeptide isolated from the hypothalamus. It has been shown to induce hypotension in the rat, to stimulate contraction of guinea pig ileum and rat uterus, and to cause relaxation of rat duodenum. There is also evidence that it acts as both a peripheral and a central nervous system neurotransmitter.
D011149	Pons	The front part of the hindbrain (RHOMBENCEPHALON) that lies between the MEDULLA and the midbrain (MESENCEPHALON) ventral to the cerebellum. It is composed of two parts, the dorsal and the ventral. The pons serves as a relay station for neural pathways between the CEREBELLUM to the CEREBRUM.	Pons Varolii,Ponte,Pons Varolius,Pontes,Varolii, Pons,Varolius, Pons
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
D002766	Cholecystokinin	A peptide, of about 33 amino acids, secreted by the upper INTESTINAL MUCOSA and also found in the central nervous system. It causes gallbladder contraction, release of pancreatic exocrine (or digestive) enzymes, and affects other gastrointestinal functions. Cholecystokinin may be the mediator of satiety.	Pancreozymin,CCK-33,Cholecystokinin 33,Uropancreozymin
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
D013004	Somatostatin	A 14-amino acid peptide named for its ability to inhibit pituitary GROWTH HORMONE release, also called somatotropin release-inhibiting factor. It is expressed in the central and peripheral nervous systems, the gut, and other organs. SRIF can also inhibit the release of THYROID-STIMULATING HORMONE; PROLACTIN; INSULIN; and GLUCAGON besides acting as a neurotransmitter and neuromodulator. In a number of species including humans, there is an additional form of somatostatin, SRIF-28 with a 14-amino acid extension at the N-terminal.	Cyclic Somatostatin,Somatostatin-14,Somatotropin Release-Inhibiting Hormone,SRIH-14,Somatofalk,Somatostatin, Cyclic,Somatotropin Release-Inhibiting Factor,Stilamin,Somatostatin 14,Somatotropin Release Inhibiting Factor,Somatotropin Release Inhibiting Hormone