scholarly journals Substance P excites GABAergic neurons in the mouse central amygdala through neurokinin 1 receptor activation

2015 ◽  
Vol 114 (4) ◽  
pp. 2500-2508 ◽  
Author(s):  
L. Sosulina ◽  
C. Strippel ◽  
H. Romo-Parra ◽  
A. L. Walter ◽  
T. Kanyshkova ◽  
...  
Keyword(s):  
Substance P ◽  
Fluorescent Protein ◽  
Input Resistance ◽  
Receptor Activation ◽  
Gabaergic Neurons ◽  
Acid Decarboxylase ◽  
Central Amygdala ◽  
Cellular Mechanisms ◽  
Action Potential Firing

Substance P (SP) is implicated in stress regulation and affective and anxiety-related behavior. Particularly high expression has been found in the main output region of the amygdala complex, the central amygdala (CE). Here we investigated the cellular mechanisms of SP in CE in vitro, taking advantage of glutamic acid decarboxylase-green fluorescent protein (GAD67-GFP) knockin mice that yield a reliable labeling of GABAergic neurons, which comprise 95% of the neuronal population in the lateral section of CE (CEl). In GFP-positive neurons within CEl, SP caused a membrane depolarization and increase in input resistance, associated with an increase in action potential firing frequency. Under voltage-clamp conditions, the SP-specific membrane current reversed at −101.5 ± 2.8 mV and displayed inwardly rectifying properties indicative of a membrane K+ conductance. Moreover, SP responses were blocked by the neurokinin type 1 receptor (NK1R) antagonist L-822429 and mimicked by the NK1R agonist [Sar9,Met(O2)11]-SP. Immunofluorescence staining confirmed localization of NK1R in GFP-positive neurons in CEl, predominantly in PKCδ-negative neurons (80%) and in few PKCδ-positive neurons (17%). Differences in SP responses were not observed between the major types of CEl neurons (late firing, regular spiking, low-threshold bursting). In addition, SP increased the frequency and amplitude of GABAergic synaptic events in CEl neurons depending on upstream spike activity. These data indicate a NK1R-mediated increase in excitability and GABAergic activity in CEl neurons, which seems to mostly involve the PKCδ-negative subpopulation. This influence can be assumed to increase reciprocal interactions between CElon and CEloff pathways, thereby boosting the medial CE (CEm) output pathway and contributing to the anxiogenic-like action of SP in the amygdala.

Renal sensory receptor activation causes prostaglandin-dependent release of substance P

1996 ◽  
Vol 270 (4) ◽  
pp. R720-R727 ◽  
Author(s):  
U. C. Kopp ◽  
D. M. Farley ◽  
L. A. Smith
Keyword(s):  
Substance P ◽  
De Novo ◽  
Receptor Activation ◽  
Sensory Receptor ◽  
Renal Nerve ◽  
Time Control ◽  
Renal Nerve Activity ◽  
Substance P Receptor ◽  
Pelvic Perfusion

Renal mechanoreceptor (MR) activation by increased ureteral pressure (increases UP) results in an increase in afferent renal nerve activity (ARNA) that is blocked by substance P receptor blockade and prostaglandin (PG) synthesis inhibition. To examine the interaction between substance P and PGs, the release of substance P and PGE into the renal pelvis was studied before and during renal pelvic perfusion with indomethacin. Before indomethacin, increases UP increased ARNA 43 +/- 6% and renal pelvic release of substance P from 11 +/- 3 to 29 +/- 8 pg/min and PGE from 319 +/- 71 to 880 +/- 146 pg/min. Indomethacin blocked the increases in ARNA and release of substance P and PGE produced by increases UP. Time control experiments showed reproducible increases in ARNA and release of substance P and PGE during increases UP. Mechanical stimulation of the renal pelvic wall in vitro resulted in an increase in PGE release from 110 +/- 8 to 722 +/- 152 pg/min, which was abolished by indomethacin, suggesting a de novo PGE synthesis. The data suggest that increases UP results in a renal pelvic release of PGE, which facilitates the release of substance P and activation of renal pelvic MR.

scholarly journals A Novel Cellular Model to Study Angiotensin II AT2 Receptor Function in Breast Cancer Cells

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Sylvie Rodrigues-Ferreira ◽  
Marina Morel ◽  
Rosana I. Reis ◽  
Françoise Cormier ◽  
Véronique Baud ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Fluorescent Protein ◽  
Receptor Activation ◽  
At1 Receptor ◽  
At2 Receptor ◽  
Cellular Model ◽  
Selective Antagonist

Recent studies have highlighted the AT1 receptor as a potential therapeutic target in breast cancer, while the role of the AT2 subtype in this disease has remained largely neglected. The present study describes the generation and characterization of a new cellular model of human invasive breast cancer cells (D3H2LN-AT2) stably expressing high levels of Flag-tagged human AT2 receptor (Flag-hAT2). These cells exhibit high-affinity binding sites for AngII, and total binding can be displaced by the AT2-selective antagonist PD123319 but not by the AT1-selective antagonist losartan. Of interest, high levels of expression of luciferase and green fluorescent protein make these cells suitable for bioluminescence and fluorescence studies in vitro and in vivo. We provide here a novel tool to investigate the AT2 receptor functions in breast cancer cells, independently of AT1 receptor activation.

Acetylcholine excites GABAergic neurons of the ferret perigeniculate nucleus through nicotinic receptors

1995 ◽  
Vol 73 (5) ◽  
pp. 2123-2128 ◽  
Author(s):  
K. H. Lee ◽  
D. A. McCormick
Keyword(s):  
Spike Activity ◽  
Membrane Conductance ◽  
Gabaergic Neurons ◽  
Local Application ◽  
Muscarinic Agonist ◽  
Action Potential Firing ◽  
Perigeniculate Nucleus ◽  
Single Spike ◽  
Hyperpolarizing Response

1. The actions of acetylcholine (ACh) on the GABAergic neurons of the perigeniculate nucleus (PGN) were investigated with the use of extra- and intracellular recording techniques in spontaneously spindling ferret thalamic slices maintained in vitro. 2. Local application of ACh to PGN neurons resulted in rapid depolarization followed by a longer lasting hyperpolarization. Neither of these responses were abolished by blockade of synaptic transmission with tetrodotoxin (TTX) nor with low Ca2+ and elevated Mg2+ solution, indicating that they are direct postsynaptic actions of ACh on PGN cells. Functionally, the rapid depolarizing response could activate both single spike activity, as well as low-threshold Ca2+ spike-mediated bursts. 3. The fast depolarizing response to ACh was selectively blocked by application of the nicotinic antagonist hexamethonium, whereas the slow hyperpolarizing response to ACh was selectively blocked by application of the muscarinic antagonist (-)scopolamine. Application of both hexamethonium and (-)scopolamine blocked the modulation of PGN action-potential firing by ACh. 4. Local application of the nicotinic agonist 1,1-dimethyl-4-phenylpiperazinium (DMPP) resulted in a depolarizing response and an increase in membrane conductance, whereas application of the muscarinic agonist DL-muscarine chloride resulted in a hyperpolarizing response and an increase in membrane conductance. When applied to spontaneously spindling PGN cells, both DMPP and DL-muscarine blocked the occurrence of spindle oscillations. However, only DMPP was associated with depolarization and the generation of single spike activity. 5. These results indicate that the GABAergic cells of the PGN possess postsynaptic nicotinic as well as muscarinic receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of substance P on colonic mechanoreceptors, motility, and sympathetic neurons

1982 ◽  
Vol 243 (4) ◽  
pp. G259-G267 ◽  
Author(s):  
J. Krier ◽  
J. H. Szurszewski
Keyword(s):  
Substance P ◽  
Synaptic Transmission ◽  
Sympathetic Neurons ◽  
Colonic Motility ◽  
Input Resistance ◽  
Intraluminal Pressure ◽  
Excitatory Postsynaptic Potentials ◽  
Postsynaptic Potentials ◽  
Recording Techniques

Intracellular recording techniques were used in vitro to analyze the effects of substance P (SP) on synaptic transmission and electrical properties of sympathetic neurons in the inferior mesenteric ganglion (IMG) of the guinea pig. Intraluminal pressure-recording techniques were used to study the effects of SP on colonic motility. Superfusion of the ganglia with SP (10(-7) to 10(-6) M) depolarized the cell soma (2--12 mV) and increased cell input resistance (8--11 M omega). These effects converted synchronous excitatory postsynaptic potentials, in response to electrical stimulation of preganglionic nerves, and asynchronous excitatory postsynaptic potentials, in response to activation of colonic mechanoreceptors, to action potentials. Administration of SP to only the colon increased basal intraluminal pressure and the frequency and amplitude of phasic changes in intraluminal pressure. These changes increased mechanoreceptor synaptic input to neurons in the IMG. We conclude that SP facilitates synaptic transmission along noradrenergic pathways and increases colonic motility.

scholarly journals A novel red fluorescence dopamine biosensor selectively detects dopamine in the presence of norepinephrine in vitro

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Chihiro Nakamoto ◽  
Yuhei Goto ◽  
Yoko Tomizawa ◽  
Yuko Fukata ◽  
Masaki Fukata ◽  
...  
Keyword(s):  
Hela Cells ◽  
Hippocampal Neurons ◽  
High Selectivity ◽  
Fluorescent Protein ◽  
Dynamic Range ◽  
Receptor Activation ◽  
Spatiotemporal Dynamics ◽  
Intracellular Loop ◽  
Brain Functions

AbstractDopamine (DA) and norepinephrine (NE) are pivotal neuromodulators that regulate a broad range of brain functions, often in concert. Despite their physiological importance, untangling the relationship between DA and NE in the fine control of output function is currently challenging, primarily due to a lack of techniques to allow the observation of spatiotemporal dynamics with sufficiently high selectivity. Although genetically encoded fluorescent biosensors have been developed to detect DA, their poor selectivity prevents distinguishing DA from NE. Here, we report the development of a red fluorescent genetically encoded GPCR (G protein-coupled receptor)-activation reporter for DA termed ‘R-GenGAR-DA’. More specifically, a circular permutated red fluorescent protein (cpmApple) was replaced by the third intracellular loop of human DA receptor D1 (DRD1) followed by the screening of mutants within the linkers between DRD1 and cpmApple. We developed two variants: R-GenGAR-DA1.1, which brightened following DA stimulation, and R-GenGAR-DA1.2, which dimmed. R-GenGAR-DA1.2 demonstrated a reasonable dynamic range (ΔF/F0 = − 43%), DA affinity (EC50 = 0.92 µM) and high selectivity for DA over NE (66-fold) in HeLa cells. Taking advantage of the high selectivity of R-GenGAR-DA1.2, we monitored DA in presence of NE using dual-color fluorescence live imaging, combined with the green-NE biosensor GRABNE1m, which has high selectivity for NE over DA (> 350-fold) in HeLa cells and hippocampal neurons grown from primary culture. Thus, this is a first step toward the multiplex imaging of these neurotransmitters in, for example, freely moving animals, which will provide new opportunities to advance our understanding of the high spatiotemporal dynamics of DA and NE in normal and abnormal brain function.

Emerging pharmacologic mechanisms of buprenorphine to explain experience of analgesia versus adverse effects

2021 ◽  
Vol 17 (7) ◽  
pp. 21-31
Author(s):  
Jeffrey Bettinger, PharmD ◽  
Himayapsill Batista Quevedo, PharmD ◽  
Jacqueline Cleary, PharmD, BCACP
Keyword(s):  
Adverse Effects ◽  
Opioid Receptor ◽  
Opioid Receptors ◽  
Partial Agonist ◽  
Clinical Trial Data ◽  
Receptor Activation ◽  
Cellular Mechanisms ◽  
Μ Opioid Receptor ◽  
Addictive Potential

Buprenorphine’s unique pharmacologic mechanisms of action lend itself to a higher level of complexity than its typical characterization as a partial agonist at μ-opioid receptors. It is well-documented that its additional activity at Δ- and κ-opioid receptors, and opioid receptor ligand 1 may be associated with varying degrees of analgesia and usual opioid-related adverse effects. However, novel downstream molecular and cellular mechanisms from μ-opioid receptor activation contain potential new insights into its overall unique effects. These include buprenorphine’s peculiar ability to induce analgesia at escalating doses, while exhibiting a plateaued effect on respiratory depression, euphoria, gastrointestinal (GI) motility, depression, anxiety, and addictive potential. Thus, this review aims to discuss several of these emerging mechanisms to gain a better understanding of these curious actions, as well as support much of this in vitro evidence with various human clinical trial data to further support buprenorphine’s place on the analgesic ladder.

scholarly journals Dopamine Increases Excitability of Pyramidal Neurons in Primate Prefrontal Cortex

2000 ◽  
Vol 84 (6) ◽  
pp. 2799-2809 ◽  
Author(s):  
Darrell A. Henze ◽  
Guillermo R. González-Burgos ◽  
Nathaniel N. Urban ◽  
David A. Lewis ◽  
German Barrionuevo
Keyword(s):  
Prefrontal Cortex ◽  
Action Potential ◽  
Pyramidal Neurons ◽  
Pyramidal Cells ◽  
Input Resistance ◽  
Initiation Site ◽  
D1 Receptor ◽  
Resting Membrane Potential ◽  
Cellular Mechanisms

Dopaminergic modulation of neuronal networks in the dorsolateral prefrontal cortex (PFC) is believed to play an important role in information processing during working memory tasks in both humans and nonhuman primates. To understand the basic cellular mechanisms that underlie these actions of dopamine (DA), we have investigated the influence of DA on the cellular properties of layer 3 pyramidal cells in area 46 of the macaque monkey PFC. Intracellular voltage recordings were obtained with sharp and whole cell patch-clamp electrodes in a PFC brain-slice preparation. All of the recorded neurons in layer 3 ( n = 86) exhibited regular spiking firing properties consistent with those of pyramidal neurons. We found that DA had no significant effects on resting membrane potential or input resistance of these cells. However DA, at concentrations as low as 0.5 μM, increased the excitability of PFC cells in response to depolarizing current steps injected at the soma. Enhanced excitability was associated with a hyperpolarizing shift in action potential threshold and a decreased first interspike interval. These effects required activation of D1-like but not D2-like receptors since they were inhibited by the D1 receptor antagonist SCH23390 (3 μM) but not significantly altered by the D2 antagonist sulpiride (2.5 μM). These results show, for the first time, that DA modulates the activity of layer 3 pyramidal neurons in area 46 of monkey dorsolateral PFC in vitro. Furthermore the results suggest that, by means of these effects alone, DA modulation would generally enhance the response of PFC pyramidal neurons to excitatory currents that reach the action potential initiation site.

Carbachol-induced synchronized rhythmic bursts in CA3 neurons of guinea pig hippocampus in vitro

1994 ◽  
Vol 72 (1) ◽  
pp. 131-138 ◽  
Author(s):  
R. Bianchi ◽  
R. K. Wong
Keyword(s):  
Membrane Potential ◽  
Guinea Pig ◽  
Mossy Fiber ◽  
Field Potential ◽  
Pyramidal Cells ◽  
Input Resistance ◽  
Gamma Aminobutyric Acid ◽  
Action Potential Firing ◽  
Potential Firing

1. Carbachol effects on CA3 hippocampal cells were studied in the absence of ionotropic glutamatergic and GABAergic transmission with intracellular and extracellular recordings from guinea pig septohippocampal slices. 2. In all experiments the perfusing solution contained ionotropic glutamate and gamma-aminobutyric acid (GABA) receptor blockers [6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 10–20 microM), 3-((+/-)-2-carboxypiperazin-4-il)propyl-1-phosphonic acid (CPP, 10–20 microM), and picrotoxin (50 microM), respectively]. Under these conditions, the excitatory and early inhibitory postsynaptic potentials, evoked in CA3 pyramidal cells by mossy fiber stimulation before the addition of the blockers, were completely suppressed. 3. Carbachol (50 microM) introduced via bath perfusion or pulse application elicited a series of rhythmic bursts with overriding action potentials. Each rhythmic burst lasted up to 30 s and repeated at intervals of 0.7–6 min. Rhythmic bursts were blocked by atropine (1 microM). 4. At membrane potentials more depolarized than -70 mV, carbachol also elicited a sustained depolarization associated with an increase in membrane input resistance and action-potential firing. This response was blocked by atropine (1 microM). 5. Carbachol can induce both rhythmic bursts and sustained depolarizations in the same cell. Rhythmic bursts were elicited when the membrane potential of the cell was more hyperpolarized than -70 mV; sustained depolarizing responses were activated by carbachol when the cell membrane potential was more depolarized than -70 mV. 6. Extracellular field potential responses in the CA3 region occurred simultaneously with rhythmic bursts, indicating the synchronization of the event in the CA3 field. Dual intracellular recordings confirmed that rhythmic bursts occurred simultaneously in CA3 hippocampal pyramidal cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Ionic mechanism of substance P actions on neurons in trigeminal root ganglia

1990 ◽  
Vol 64 (1) ◽  
pp. 273-281 ◽  
Author(s):  
I. Spigelman ◽  
E. Puil
Keyword(s):  
Substance P ◽  
Voltage Clamp ◽  
Reversal Potential ◽  
Input Resistance ◽  
K Channel ◽  
Resting Membrane Potential ◽  
Channel Blockers ◽  
Ionic Mechanism ◽  
Trigeminal Root

1. Responses of primary sensory neurons to substance P applications by perfusion were studied with intracellular recording techniques in in vitro slice preparations of trigeminal root ganglia (guinea pigs). Application of substance P in micromolar doses produced reversible depolarizations of 2–47 mV in 48 out of 64 neurons. The depolarizing influence facilitated repetitive spike discharge evoked by current-pulse injection. Evidence of desensitization was observed during prolonged or repeated applications of the peptide. 2. The responses to substance P were associated with decreased input resistance, although increased input resistance was observed in neurons where the resting membrane potential was compensated with DC injection. In single-electrode voltage-clamp (SEVC) recordings, substance P evoked an inward shift in the holding current and reduced an outwardly rectifying component in the I-V relationships. The reversal potential for the substance P response could not be determined. These results suggested that the perikaryal response to substance P has a complex ionic mechanism involving activation and deactivation of membrane conductances. 3. Substance P-induced depolarizations were greatly attenuated during perfusion with solutions that were deficient in [Na+] or [Mg2+] and were not significantly affected during perfusion with low-[Ca2+]-, CO2(+)-containing solutions. 4. In the voltage-clamp investigations, an inward current contributed to the substance P responses during combined application with the K(+)-channel blockers, 4-aminopyridine (4-AP) and tetraethylammonium (TEA). This current was not abolished by the inclusion of CsCl in the perfusing solution or by internal Cs+ application from the recording electrode, suggesting that an anomalous inward rectifier was not involved in the responses to substance P.(ABSTRACT TRUNCATED AT 250 WORDS)

Sign in / Sign up

Export Citation Format

Share Document