scholarly journals Cannabidiol activates neuronal Kv7 channels

2021 ◽  
Author(s):  
Zachary Niday ◽  
Laurel Heckman ◽  
Sooyeon Jo ◽  
Han-Xiong Bear Zhang ◽  
Akie Fujita ◽  
...  
Keyword(s):  
Antiepileptic Drug ◽  
Hippocampal Neurons ◽  
Large Scale ◽  
Voltage Dependence ◽  
Cannabis Sativa ◽  
M Current ◽  
Kv7 Channels ◽  
Low Concentrations ◽  
Cervical Ganglion ◽  
Ganglion Neurons

Cannabidiol (CBD), a chemical found in the Cannabis sativa plant, is a clinically effective antiepileptic drug whose mechanism of action is unknown. Using a fluorescence-based thallium flux assay, we performed a large-scale screen and found enhancement of flux through heterologously-expressed human Kv7.2/7.3 channels by CBD. Using patch clamp recordings, we found that CBD at low concentrations activates Kv7.2/7.3 channels at subthreshold voltages, with 100 nM CBD producing a doubling of current at -50 mV. CBD shifted the voltage-dependence of channels in the hyperpolarizing direction, producing a shift in the midpoint of activation by about ~-14 mV at 300 nM. CBD also effectively enhanced native M-current in both mouse superior cervical ganglion neurons and rat hippocampal neurons. The potent enhancement of Kv2/7.3 channels by CBD seems likely to contribute to its effectiveness as an antiepileptic drug by reducing neuronal hyperexcitability.

scholarly journals Ethanol Elevates Excitability of Superior Cervical Ganglion Neurons by Inhibiting Kv7 Channels in a Cell Type-Specific and PI(4,5)P2-Dependent Manner

2019 ◽  
Vol 20 (18) ◽  
pp. 4419 ◽  
Author(s):  
Kwon-Woo Kim ◽  
Keetae Kim ◽  
Hyosang Lee ◽  
Byung-Chang Suh
Keyword(s):  
Membrane Potential ◽  
Superior Cervical Ganglion ◽  
Neuronal Excitability ◽  
Sympathetic Neurons ◽  
Expression System ◽  
Dependent Manner ◽  
Cellular Targets ◽  
Kv7 Channels ◽  
Cervical Ganglion ◽  
Ganglion Neurons

Alcohol causes diverse acute and chronic symptoms that often lead to critical health problems. Exposure to ethanol alters the activities of sympathetic neurons that control the muscles, eyes, and blood vessels in the brain. Although recent studies have revealed the cellular targets of ethanol, such as ion channels, the molecular mechanism by which alcohol modulates the excitability of sympathetic neurons has not been determined. Here, we demonstrated that ethanol increased the discharge of membrane potentials in sympathetic neurons by inhibiting the M-type or Kv7 channel consisting of the Kv7.2/7.3 subunits, which were involved in determining the membrane potential and excitability of neurons. Three types of sympathetic neurons, classified by their threshold of activation and firing patterns, displayed distinct sensitivities to ethanol, which were negatively correlated with the size of the Kv7 current that differs depending on the type of neuron. Using a heterologous expression system, we further revealed that the inhibitory effects of ethanol on Kv7.2/7.3 currents were facilitated or diminished by adjusting the amount of plasma membrane phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). These results suggested that ethanol and PI(4,5)P2 modulated gating of the Kv7 channel in superior cervical ganglion neurons in an antagonistic manner, leading to regulation of the membrane potential and neuronal excitability, as well as the physiological functions mediated by sympathetic neurons.

Immunogold labeling of CMP-KDO synthetase produced by recombinant E. Coli cells

1987 ◽  
Vol 45 ◽  
pp. 924-925
Author(s):  
F. A. Durum ◽  
R. G. Goldman ◽  
T. J. Bolling ◽  
M. F. Miller
Keyword(s):  
Inclusion Bodies ◽  
Large Scale ◽  
Recombinant Dna ◽  
Test System ◽  
Cell Protein ◽  
Gram Negative Bacteria ◽  
Cytoplasmic Inclusions ◽  
Isolation And Purification ◽  
E Coli ◽  
Low Concentrations

CMP-KDO synthetase (CKS) is an enzyme which plays a key role in the synthesis of LPS, an outer membrane component unique to gram negative bacteria. CKS activates KDO to CMP-KDO for incorporation into LPS. The enzyme is normally present in low concentrations (0.02% of total cell protein) which makes it difficult to perform large scale isolation and purification. Recently, the gene for CKS from E. coli was cloned and various recombinant DNA constructs overproducing CKS several thousandfold (unpublished data) were derived. Interestingly, no cytoplasmic inclusions of overproduced CKS were observed by EM (Fig. 1) which is in contrast to other reports of large proteinaceous inclusion bodies in various overproducing recombinant strains. The present immunocytochemical study was undertaken to localize CKS in these cells.Immune labeling conditions were first optimized using a previously described cell-free test system. Briefly, this involves soaking small blocks of polymerized bovine serum albumin in purified CKS antigen and subjecting them to various fixation, embedding and immunochemical conditions.

Fast NMDA Receptor–Mediated Synaptic Currents in Neurons From Mice Lacking the ε2 (NR2B) Subunit

2000 ◽  
Vol 83 (1) ◽  
pp. 616-620 ◽  
Author(s):  
Kenneth R. Tovar ◽  
Kathleen Sprouffske ◽  
Gary L. Westbrook
Keyword(s):  
Nmda Receptor ◽  
Hippocampal Neurons ◽  
Postsynaptic Membrane ◽  
Synaptic Activity ◽  
Wild Type ◽  
Nmda Receptor Subunit ◽  
Deactivation Kinetics ◽  
Low Concentrations ◽  
Specific Antagonist

The N-methyl-d-aspartate (NMDA) receptor has been implicated in the formation of synaptic connections. To investigate the role of the ε2 (NR2B) NMDA receptor subunit, which is prominently expressed during early development, we used neurons from mice lacking this subunit. Although ε2−/− mice die soon after birth, we examined whether NMDA receptor targeting to the postsynaptic membrane was dependent on the ε2 subunit by rescuing hippocampal neurons from these mice and studying them in autaptic cultures. In voltage-clamp recordings, excitatory postsynaptic currents (EPSCs) from ε2−/− neurons expressed an NMDA receptor–mediated EPSC that was apparent as soon as synaptic activity developed. However, compared with wild-type neurons, NMDA receptor–mediated EPSC deactivation kinetics were much faster and were less sensitive to glycine, but were blocked by Mg2+ or AP5. Whole cell currents from ε2−/− neurons were also more sensitive to block by low concentrations of Zn2+ and much less sensitive to the ε2-specific antagonist ifenprodil than wild-type currents. The rapid NMDA receptor–mediated EPSC deactivation kinetics and the pharmacological profile from ε2−/−neurons are consistent with the expression of ζ1/ε1 diheteromeric receptors in excitatory hippocampal neurons from mice lacking the ε2 subunit. Thus ε1 can substitute for the ε2 subunit at synapses and ε2 is not required for targeting of NMDA receptors to the postsynaptic membrane.

Low concentrations of muscarine potentiate M-current in bullfrog sympathetic B-neurones

1997 ◽  
Vol 67 (1-2) ◽  
pp. 89-96 ◽  
Author(s):  
Dmitri E Kurennyi ◽  
Hsinyo Chen ◽  
Peter A Smith
Keyword(s):  
M Current ◽  
Low Concentrations

scholarly journals Sexual dimorphism in prostacyclin-mimetic responses of rat mesenteric and coronary arteries.

2021 ◽  
Author(s):  
Samuel Baldwin ◽  
Elizabeth Forrester ◽  
Lauren McEwan ◽  
Iain Greenwood
Keyword(s):  
Experimental Approach ◽  
Mesenteric Arteries ◽  
High Concentration ◽  
Male And Female ◽  
Sexual Dimorphisms ◽  
Kv7 Channels ◽  
Low Concentrations ◽  
Ip Receptor ◽  
Female Wistar Rats ◽  
Arterial Tone

Background and purpose- Prostacyclin mimetics are widely used clinically. As such it is pertinent to understand the mechanisms underlying the vasoactive response to such agents, yet to date, no study has considered sex as a factor. The aim of this study was to characterise the effect of prostacyclin mimetics, Iloprost and MRE-269, on precontracted arterial tone from male and female Wistar arteries. As a secondary consideration, we investigated Kcnq-encoded KV7 channels as potential downstream targets of prostacyclin-IP-receptor mediated signalling. Experimental approach- Relative mRNA transcript and protein abundance were determined by RT-qPCR and immunocytochemistry respectively. The effect of Iloprost and MRE-269 was determined on pre-contracted arterial tone in the presence of pharmacological modulators of potassium channels and molecular interreference of KV7.1 within 2nd order mesenteric and left anterior descending arteries from male and female Wistar rats. Key results- Iloprost evoked a bi-phasic response in male mesenteric arteries, at low concentrations relaxing, then contracting the vessel at high concentration in a process attributed to IP and EP3 receptors respectively. Secondary contraction was absent in the females, potentially underpinned by a reduction in Ptger3. Pharmacological inhibition and molecular interference of KV7.1 significantly attenuated MRE-269 mediated relaxation in male and female Wistar in Diestrus / Metoestrous, but not Pro-oestrus / Oestrus. Conclusions and implications- Stark sexual dimorphisms in Iloprost mediated vasoactive responses are present within mesenteric arteries. KV7.1 is implicated in IP-receptor mediated vasorelaxation and is impaired by the Oestrus cycle.

Sign in / Sign up

Export Citation Format

Share Document