GABA-Mimetic Actions of Withania somnifera on Substantia Gelatinosa Neurons of the Trigeminal Subnucleus Caudalis in Mice

2013 ◽  
Vol 41 (05) ◽  
pp. 1043-1051 ◽  
Author(s):  
Hua Yin ◽  
Dong Hyu Cho ◽  
Soo Joung Park ◽  
Seong Kyu Han

The plant Withania somnifera (WS), also known as Ashwagandha, has been used widely in traditional medicine systems in India and Nepal (Ayurveda), and has been accepted to cure various ailments. In this study, the whole-cell patch clamp technique was performed to examine the mechanism of action of WS on the SG neurons of the Vc from mouse brainstem slices. In whole-cell patch clamp mode, methanol extract of Withania somnifera (mWS) induced short-lived and repeatable inward currents in all SG neurons tested (31.3±8.51 pA, n = 7) using a high chloride pipette solution. The mWS-induced inward currents were concentration dependent and maintained in the presence of tetrodotoxin (TTX), a voltage gated Na + channel blocker, CNQX, a non-NMDA glutamate receptor antagonist, AP5, an NMDA receptor antagonist and strychnine, a glycine receptor antagonist. The mWS induced currents were blocked by picrotoxin, a GABAA receptor antagonist. These results show that mWS has an inhibitory effects on SG neurons of the Vc through GABAA receptor-mediated activation of chloride ion channels, indicating that mWS contains compounds with sedative effects on the central nervous system. These results also suggest that mWS may be a potential target for modulating orofacial pain processing.

Author(s):  
Thao Nguyen Thi Phuong ◽  
Seon Hui Jang ◽  
Santosh Rijal ◽  
Woo Kwon Jung ◽  
Junghyun Kim ◽  
...  

Linalool, a major odorous constituent in essential oils extracted from lavender, is known to have a wide range of physiological effects on humans including pain management. The substantia gelatinosa (SG) of the trigeminal subnucleus caudalis (Vc) is involved in transmission of orofacial nociceptive responses through thin myelinated A[Formula: see text] and unmyelinated C primary afferent fibers. Up to date, the orofacial antinociceptive mechanism of linalool concerning SG neurons of the Vc has not been completely clarified yet. To fill this knowledge gap, whole-cell patch-clamp technique was used in this study to examine how linalool acted on SG neurons of the Vc in mice. Under a high chloride pipette solution, non-desensitizing and repeatable linalool-induced inward currents were preserved in the presence of tetrodotoxin (a voltage-gated Na[Formula: see text]channel blocker), CNQX (a non-NMDA glutamate receptor antagonist), and DL-AP5 (an NMDA receptor antagonist). However, linalool-induced inward currents were partially suppressed by picrotoxin (a GABA[Formula: see text] receptor antagonist) or strychnine (a glycine receptor antagonist). These responses were almost blocked in the presence of picrotoxin and strychnine. It was also found that linalool exhibited potentiation with GABA- and glycine-induced responses. Taken together, these data show that linalool has GABA- and glycine-mimetic effects, suggesting that it can be a promising target molecule for orofacial pain management by activating inhibitory neurotransmission in the SG area of the Vc.


2011 ◽  
Vol 35 (5) ◽  
pp. 500-506 ◽  
Author(s):  
Naoki Oshima ◽  
Hiroo Kumagai ◽  
Kamon Iigaya ◽  
Hiroshi Onimaru ◽  
Akira Kawai ◽  
...  

2006 ◽  
Vol 2006 ◽  
pp. 1-7 ◽  
Author(s):  
Daniel Granfeldt ◽  
Olle Harbecke ◽  
Åse Björstad ◽  
Anna Karlsson ◽  
Claes Dahlgren

We have investigated calcium-induced secretion in human neutrophils, using a whole-cell patch-clamp technique. Mobilization of subcellular granules to the cell membrane was followed as the change in membrane capacitance (△Cm). Both the magnitude and the kinetics of the response differed between low and high concentrations of Ca2+. A sustained secretion following a short lag phase was induced by high concentrations of Ca2+(100μM and higher). A stable plateau was reached after 5–7 minutes at△Cmvalues corresponding to values expected after all specific as well as azurophil granules have been mobilized. Capacitance values of the same magnitude could be obtained also at lower Ca2+concentrations, but typically no stable plateau was reached within the measuring time. In contrast to previous studies, we were unable to detect any pattern of secretion corresponding to a distinct submaximal response or selective mobilization of granule subsets specified by their Ca2+-sensitivity.


1994 ◽  
Vol 299 (1) ◽  
pp. 37-40 ◽  
Author(s):  
P M Smith ◽  
D V Gallacher

The tumour-promoting agent thapsigargin has been shown to inhibit the microsomal Ca(2+)-ATPase and cause Ca2+ mobilization in a variety of cell types including exocrine acinar cells [Bird, Obie and Putney (1992) J. Biol. Chem. 267, 18382-18386]. When applied to acutely isolated lacrimal acinar cells, thapsigargin caused a slow biphasic activation of both the Ca(2+)-dependent K+ and Cl- currents measured using the whole-cell patch-clamp technique. If the only action of thapsigargin is to inhibit sequestration into Ca2+ pools, then Ca2+ mobilization following exposure to thapsigargin indicates that there is a significant ‘leak’ of Ca2+ into the cytoplasm, which is normally countered by Ca(2+)-ATPase activity. In the present study, we introduced the Ins(1,4,5)P3 receptor antagonist heparin (200 micrograms/ml) into lacrimal acinar cells via the patch-clamp pipette. Following a 5 min preincubation in the presence of heparin, neither acetylcholine (1 microM) nor thapsigargin (1 microM) caused any significant increase in either Ca(2+)-dependent current. Caffeine has been shown to suppress basal Ins(1,4,5)P3 levels in exocrine acinar cells [Toescu, O'Neill, Petersen and Eisner (1992) J. Biol. Chem. 267, 23467-23470]. Preincubation with caffeine (10 mM) also inhibited the response to subsequent exposure to thapsigargin. These data suggest that, in acutely isolated lacrimal cells, the source of the Ca2+ leak which gives rise to Ca2+ mobilization following inhibition of Ca2+ re-uptake by thapsigargin is Ca2+ release, from Ins(1,4,5)P3-dependent Ca2+ pools, caused by resting Ins(1,4,5)P3 levels.


2012 ◽  
Vol 302 (11) ◽  
pp. C1599-C1608 ◽  
Author(s):  
Kiril L. Hristov ◽  
Muyan Chen ◽  
Serge A. Y. Afeli ◽  
Qiuping Cheng ◽  
Eric S. Rovner ◽  
...  

The functional role of the voltage-gated K+ (KV) channels in human detrusor smooth muscle (DSM) is largely unexplored. Here, we provide molecular, electrophysiological, and functional evidence for the expression of KV2.1, KV2.2, and the electrically silent KV9.3 subunits in human DSM. Stromatoxin-1 (ScTx1), a selective inhibitor of KV2.1, KV2.2, and KV4.2 homotetrameric channels and of KV2.1/9.3 heterotetrameric channels, was used to examine the role of these channels in human DSM function. Human DSM tissues were obtained during open bladder surgeries from patients without a history of overactive bladder. Freshly isolated human DSM cells were studied using RT-PCR, immunocytochemistry, live-cell Ca2+ imaging, and the perforated whole cell patch-clamp technique. Isometric DSM tension recordings of human DSM isolated strips were conducted using tissue baths. RT-PCR experiments showed mRNA expression of KV2.1, KV2.2, and KV9.3 (but not KV4.2) channel subunits in human isolated DSM cells. KV2.1 and KV2.2 protein expression was confirmed by Western blot analysis and immunocytochemistry. Perforated whole cell patch-clamp experiments revealed that ScTx1 (100 nM) inhibited the amplitude of the voltage step-induced KV current in freshly isolated human DSM cells. ScTx1 (100 nM) significantly increased the intracellular Ca2+ level in DSM cells. In human DSM isolated strips, ScTx1 (100 nM) increased the spontaneous phasic contraction amplitude and muscle force, and enhanced the amplitude of the electrical field stimulation-induced contractions within the range of 3.5–30 Hz stimulation frequencies. These findings reveal that ScTx1-sensitive KV2-containing channels are key regulators of human DSM excitability and contractility and may represent new targets for pharmacological or genetic intervention for bladder dysfunction.


2016 ◽  
Vol 44 (02) ◽  
pp. 389-400 ◽  
Author(s):  
Hua Yin ◽  
Janardhan Prasad Bhattarai ◽  
Sun Mi Oh ◽  
Soo Joung Park ◽  
Dong Kuk Ahn ◽  
...  

The substantia gelatinosa (SG) of the trigeminal subnucleus caudalis (Vc) receives nociceptive afferent inputs from thin-myelinated A[Formula: see text] fibers and unmyelinated C fibers and has been shown to be involved in the processing of orofacial nociceptive information. Scutellaria baicalensis Georgi (Huang-Qin, SbG), one of the 50 fundamental herbs of Chinese herbology, has been used historically as anti-inflammatory and antineoplastic medicine. Baicalin, one of the major compounds of SbG, has been reported to have neuroprotective, anti-inflammatory and analgesic effects. However, the receptor type activated by baicalin and its precise action mechanism on the SG neurons of Vc have not yet been studied. The whole-cell patch clamp technique was performed to examine the ion channels activated by baicalin on the SG neurons of Vc. In high Cl[Formula: see text] pipette solution, the baicalin (300[Formula: see text][Formula: see text]M) induced repeatable inward currents ([Formula: see text][Formula: see text]pA, [Formula: see text]) without desensitization on all the SG neurons tested. Further, the inward currents showed a concentration (0.1–3[Formula: see text]mM) dependent pattern. The inward current was sustained in the presence of tetrodotoxin (0.5[Formula: see text][Formula: see text]M), a voltage sensitive Na[Formula: see text] channel blocker. In addition, baicalin-induced inward currents were reduced in the presence of picrotoxin (50[Formula: see text][Formula: see text]M), a GABAA receptor antagonist, flumazenil (100[Formula: see text][Formula: see text]M), a benzodiazepine-sensitive GABAA receptor antagonist, and strychnine (2[Formula: see text][Formula: see text]M), a glycine receptor antagonist, respectively. These results indicate that baicalin has inhibitory effects on the SG neurons of the Vc, which are due to the activation of GABAA and/or the glycine receptor. Our results suggest that baicalin may be a potential target for orofacial pain modulation.


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