Neurokinin-1 receptor resensitization results from a change in G protein coupling and not receptor recycling
Biochemistry & Molecular Biology; Cell Biology; Life Sciences & Biomedicine - Other; Topics
Bennett V J; Perrine S A; Simmons M A
Faseb Journal
2003
2003-03
Journal Article or Conference Abstract Publication
n/a
Conformational comparisons of a series of tachykinin peptide analogs
Pharmacology & Pharmacy; escherichia-coli; nmr; dynamics; nuclear-magnetic-resonance; substance-p receptor; agonists; neuropeptides; bradykinin; molecular modeling investigations; sds micelles
Previous studies have shown differences in the biological activity and the structure of two naturally occurring tachykinin peptides, substance P (SP, RPKPQQFFGLM-NH2),and ranatachykinin C (RTKC, HNPASFIGLM-NH2). To further understand the basis for these differences, four analogs that selectively incorporate the amino acid differences between SP and RTKC have been synthesized for study. The four peptide analogs studied have the following amino acid sequences: SP2-11, also known as des-Arg SP (PKPQQFFGLM-NH2); Q5A-SP (RPKPAQFFGLM-NH2); Q6S-SP (RPKPQSFFGLM-NH2); and Q5AQ6S-SP (RPKPASFFGLM-NH2). Nuclear magnetic resonance spectroscopy and molecular modeling calculations were performed on SP, RTKC, SP2-11, Q5A-SP, Q6S-SP, and Q5AQ6S-SP to compare their conformational differences and similarities in the presence of the membrane mimetic system sodium dodecyl sulfate. The molecular modeling data of the analogs Q5A-SP and Q6S-SP show residues 1-3 have a random conformation and residues 4-8 have a helical structure, while the C-terminus contains a poly C-7 conformation that is similar to SP but different from RTKC., The molecular modeling data of the analogs SP2-11 and Q5AQ6S-SP show a continuous helix conformation for residues 4-11 at the C-terminus, which is different from SP but similar to RTKC. These structural differences are related to the functional differences of binding of the peptides at the SP receptor (NK1).
Beard D J; Perrine S A; Phillips E; Hoque S; Conerly S; Tichenor C; Simmons M A; Young J K
Journal of Medicinal Chemistry
2007
2007-12
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1021/jm070577s" target="_blank" rel="noreferrer noopener">10.1021/jm070577s</a>
Acute nicotine and phencyclidine increase locomotor activity of the guinea pig
Biochemistry & Molecular Biology; Cell Biology; Life Sciences & Biomedicine - Other; Topics
Simmons M A; Hudzik T J
Faseb Journal
2009
2009-04
Journal Article
n/a
Changes of the responses of single sympathetic ganglionic neurones to substance P following desensitization
adenylate-cyclase; binding; cells; desensitization; G protein; inhibition; k+ current; kinase-c; M current; muscarine; Neurosciences & Neurology; Pharmacology & Pharmacy; phosphorylation; protein alpha-subunits; receptor; rgs proteins; Substance P
1 The neuropeptide substance P (SP) exerts an excitatory effect on sympathetic neurones by inhibiting a time- and voltage-dependent potassium current. During prolonged application of SP, the response desensitizes. The changes in kinetics of the SP response in single neurones after desensitization have been studied in an attempt to gain some insight as to the molecular mechanism of desensitization in live, functioning neurones. 2 Desensitization to SP resulted in subsequent SP responses being smaller, but the time course was unchanged in desensitized cells compared with non-desensitized cells. 3 Experimental manipulations were performed to decrease receptor and G protein function for comparison to desensitization. Intracellular application of GDP betaS, to decrease G protein function, led to successive responses to agonist becoming smaller and slower. When functional muscarinic receptors were decreased by extracellular application of propylbenzilylcholine mustard (PrBCM), the response to muscarine became smaller, but the time course was unchanged compared with the change in time course produced by PrBCM vehicle alone. 4 The results have also been compared with simulations from a mathematical model of drug-receptor-G protein interactions. Under a constrained set of conditions, the model predicts that decreasing the size of the G protein pool will decrease both the magnitude and the time course of the response to agonist. Decreasing receptor levels results in a more efficient decrease in the magnitude of the response but no change in the time course of the response. 5 These data provide evidence that desensitization of the response to SP in single neurones results from a decrease in functional receptors.
Simmons M A
Journal of Autonomic Pharmacology
2001
2001-04
Journal Article
<a href="http://doi.org/10.1046/j.1365-2680.2001.00214.x" target="_blank" rel="noreferrer noopener">10.1046/j.1365-2680.2001.00214.x</a>
Repeated stressor exposure regionally enhances beta-adrenergic receptor-mediated brain IL-1 beta production
Anhedonia; antidepressant treatments; Chronic mild stress; chronic psychosocial stress; Cytokine; depression; depressive-like behavior; hippocampal neurogenesis; Immunology; inflammatory cytokines; ligand-binding; messenger-rna; Neurosciences & Neurology; Norepinephrine; paraventricular nucleus; prefrontal cortex; Psychiatry; rat; rat-brain; Receptor binding; Sensitization
It has been proposed that increased brain cytokines during repeated stressor exposure can contribute to neuropathological changes that lead to the onset of depression. Previous studies demonstrate that norepinephrine acting via beta-adrenergic receptors (beta-ARs) mediate brain IL-1 production during acute stressor exposure. The aim of the current studies was to examine how the regulation of brain cytokines by adrenergic signaling might change following repeated stressor exposure. Fischer rats were exposed to four days of chronic mild stress and 24 h after the last stressors beta-AR expression, norepinephrine turnover, and beta-AR-mediated induction of brain IL-1 were measured in limbic areas (e.g. hypothalamus, hippocampus, amygdala, and prefrontal cortex) and brainstem. Repeated stressor exposure resulted in decreases in beta-AR expression (B-max) measured by saturation binding curves in many limbic brain areas, while an increase was observed in the brainstem. This coincided with significant increases in norepinephrine turnover in the prefrontal cortex, hypothalamus, and amygdala, a significant increase in norepinephrine turnover was not observed in the hippocampus or brainstem. Stress increased overall IL-1 production in the amygdala (both basal and stimulated). While stress did not affect basal IL-1 levels in any other brain area, central administration of isoproterenol (a beta-AR agonist) augmented IL-1 production in the hypothalamus of stressed animals. These data indicate that repeated stressor exposure results in brain area specific enhancements in beta-AR-mediated IL-1 production and extends current knowledge of stress-induced enhancement of brain cytokine beyond sensitized response to immunological stimuli. (C) 2012 Elsevier Inc. All rights reserved.
Porterfield V M; Gabella K M; Simmons M A; Johnson J D
Brain Behavior and Immunity
2012
2012-11
Journal Article
<a href="http://doi.org/10.1016/j.bbi.2012.08.001" target="_blank" rel="noreferrer noopener">10.1016/j.bbi.2012.08.001</a>
Neurokinin-1 receptor resensitization precedes receptor recycling.
Adenosine Triphosphate/pharmacology; Animals; Binding; Calcium/metabolism; CHO Cells; Competitive; Cricetinae; Guanylyl Imidodiphosphate/pharmacology; Neurokinin-1/*metabolism; Phosphorylation; Rats; Receptors; Substance P/metabolism
Following agonist binding, neurokinin-1 receptors undergo rapid desensitization followed by internalization and recycling. Desensitization requires receptor phosphorylation but does not require internalization, whereas resensitization is thought to require internalization and recycling. Our previous data, however, have suggested that, following activation and desensitization, the return of responsiveness to the neurokinin-1 agonist substance P (termed "resensitization") occurs hours before internalized receptors are recycled back to the plasma membrane. To further investigate this novel mechanism of neurokinin-1 receptor resensitization, we have studied the time courses of neurokinin-1 receptor responsiveness, recycling, and dephosphorylation by measuring cellular Ca(2+) responses, ligand-receptor binding, and receptor phosphorylation, respectively. Concentration-response curves and competition binding curves were obtained at various times following desensitization. The effects of the nonhydrolyzable GTP analog Gpp(NH)p on substance P binding were also studied to assess receptor-G protein coupling. After receptor activation and desensitization, Ca(2+) signaling in response to substance P occurred within 90 min, whereas the return of receptor binding required 240 min. Receptor dephosphorylation was greater than 90% complete 20 min after agonist washout. In addition, the return of substance P responsiveness coincided with a return in sensitivity of substance P binding to Gpp(NH)p, indicating a return in receptor-G protein coupling. These data show that the resensitization of responsiveness to substance P precedes receptor recycling. This may result from a conversion of nonfunctional neurokinin-1 receptors to functional receptors at the plasma membrane.
Bennett V J; Perrine S A; Simmons M A
The Journal of pharmacology and experimental therapeutics
2005
2005-06
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1124/jpet.104.079954" target="_blank" rel="noreferrer noopener">10.1124/jpet.104.079954</a>
A novel mechanism of neurokinin-1 receptor resensitization.
Animals; Cell Membrane/drug effects/metabolism; CHO Cells; Concanavalin A/pharmacology; Cricetinae; Monensin/pharmacology; Neurokinin-1/*agonists/*metabolism; Phosphorylation/drug effects; Rats; Receptors
Prolonged or repeated activation of many G protein-coupled receptors induces rapid desensitization followed by a period during which receptors are resensitized. In this study, concanavalin A (Con A) and monensin were used to investigate the mechanisms of desensitization and resensitization of the neurokinin-1 receptor. Con A inhibits internalization, whereas monensin prevents receptor recycling. The effects of Con A and monensin on desensitization, resensitization, receptor phosphorylation, endocytosis, and recycling of the neurokinin-1 receptor were assessed. Desensitization was defined as the decrease in the ability of substance P (SP) to elicit an intracellular Ca2+ response after a prolonged SP exposure. Resensitization was characterized as the return of SP responsiveness. Under control conditions, desensitization occurred after a 5-min exposure to agonist. Resensitization was evident 30 min after agonist washout. Neither monensin nor Con A prevented desensitization. Monensin completely inhibited resensitization, whereas Con A decreased but did not completely block resensitization. Receptor phosphorylation was increased after agonist activation and returned to basal levels after a recovery period. Neither Con A nor monensin altered the amount of agonist-specific receptor phosphorylation. Receptor binding analysis showed that plasma membrane receptors were internalized after a 5-min agonist exposure. Receptor recycling was not observed after a 1-h recovery period; however, resensitization was apparent. Taken together, these results suggest that rapid neurokinin-1 receptor desensitization can occur without receptor internalization and that resensitization occurs before receptor recycling.
Bennett V J; Perrine S A; Simmons M A
The Journal of pharmacology and experimental therapeutics
2002
2002-12
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1124/jpet.102.040378" target="_blank" rel="noreferrer noopener">10.1124/jpet.102.040378</a>
Tachykinin peptide-induced activation and desensitization of neurokinin 1 receptors.
Amino Acid Sequence; Animals; CHO Cells; Cricetinae; Down-Regulation/*drug effects; Electrophysiology; Ligands; Neurokinin-1/*agonists/*metabolism; Potassium/metabolism; Protein Binding; Rana catesbeiana; Receptors; Tachykinins/chemistry/*pharmacology
The actions of four tachykinins on inhibition and desensitization of the
Perrine S A; Bennett V J; Simmons M A
Peptides
2003
2003-03
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/s0196-9781(03)00064-0" target="_blank" rel="noreferrer noopener">10.1016/s0196-9781(03)00064-0</a>
Localization and function of NK(3) subtype tachykinin receptors of layer V pyramidal neurons of the guinea-pig medial prefrontal cortex.
Animals; Autoradiography/methods; Dose-Response Relationship; Drug; Drug Interactions; Excitatory Amino Acid Antagonists/pharmacology; Excitatory Postsynaptic Potentials/drug effects/radiation effects; Guinea Pigs; In Vitro Techniques; Iodine Isotopes/pharmacokinetics; Male; Membrane Potentials/drug effects/physiology/radiation effects; Neurokinin B/analogs & derivatives/pharmacokinetics; Neurokinin-3/agonists/antagonists & inhibitors/*metabolism; Patch-Clamp Techniques; Peptide Fragments/pharmacology; Prefrontal Cortex/*cytology; Protein Binding/drug effects; Pyramidal Cells/drug effects/*metabolism; Quinolines/pharmacology; Quinoxalines/pharmacology; Receptors; Substance P/analogs & derivatives/pharmacology; Valine/analogs & derivatives/pharmacology
The NK(3) subtype of tachykinin receptor has been implicated as a modulator of synaptic transmission in several brain regions, including the cerebral cortex. The localization and expression of NK(3) receptors within the brain vary from species to species. In addition, the pharmacology of NK(3) receptor-specific antagonists shows significant species variability. Among commonly used animal models, the pharmacology of the guinea-pig NK(3) receptor most closely resembles that of the human NK(3) receptor. Here, we provide anatomical localization studies, receptor binding studies, and studies of the electrophysiological effects of NK(3) receptor ligands of guinea-pig cortex using two commercially available ligands, the NK(3) receptor peptide analog agonist senktide, and the quinolinecarboxamide NK(3) receptor antagonist SB-222,200. Saturation binding studies with membranes isolated from guinea-pig cerebral cortex showed saturable binding consistent with a single high affinity site. Autoradiographic studies revealed dense specific binding in layers II/III and layer V of the cerebral cortex. For electrophysiological studies, brain slices were prepared from prefrontal cortex of 3- to 14-day-old guinea pigs. Whole cell recordings were made from layer V pyramidal neurons. In current clamp mode with a K(+)-containing pipette solution, senktide depolarized the pyramidal neurons and led to repetitive firing of action potentials. In voltage clamp mode with a Cs(+)-containing pipette solution, senktide application produced an inward current and a concentration-dependent enhancement of the amplitude and the frequency of spontaneous excitatory postsynaptic potentials. The glutamatergic nature of these events was demonstrated by block by glutamate receptor antagonists. The effects of senktide were blocked by SB-222,200, an NK(3) receptor antagonist. Taken together, these results are consistent with a functional role for NK(3) receptors located on neurons in the cerebral cortex. In layer V pyramidal neurons of the medial prefrontal cortex, activation of the NK(3) receptor system plays an excitatory role in modulating synaptic transmission.
Simmons M A; Sobotka-Briner C D; Medd A M
Neuroscience
2008
2008-10
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/j.neuroscience.2008.08.037" target="_blank" rel="noreferrer noopener">10.1016/j.neuroscience.2008.08.037</a>