Discrimination between subtypes of apamin‐sensitive Ca2+‐ activated K+ channels by gallamine and a novel bis‐quaternary quinolinium cyclophane, UCL 1530

Dunn, Philip M.; Benton, David; Rosa, Joaquin Campos; Ganellin, C. Robin; Jenkinson, D. H.

doi:10.1111/j.1476-5381.1996.tb15151.x

Cited by 44 publications

(23 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These pipettes had a resistance of 2–5 MΩ when measured in the bath solution containing (m M ): NaCl 154, KCl 4.7, MgCl 2 1.2, CaCl 2 2.5, glucose 5.6, HEPES 10, pH 7.4. Drugs were applied rapidly through a seven‐barrel manifold composed of fused glass capillaries inserted into a common outlet tube with a tip diameter of ∼200 μm (see Dunn et al ., 1996). Solutions were delivered by gravity flow from independent reservoirs placed above the preparation.…”

Section: Methodsmentioning

confidence: 99%

Rat chromaffin cells lack P2X receptors while those of the guinea‐pig express a P2X receptor with novel pharmacology

Liu

Dunn

King

et al. 1999

British J Pharmacology

View full text Add to dashboard Cite

1 Whole-cell patch-clamp recording was used to determine the functional expression and pharmacological properties of P2X receptors in chroma n cells dissociated from adrenal medullae of rats and guinea-pigs. 2 In rat chroma n cells maintained in culture for 1 ± 7 days, ATP and UTP failed to evoke any detectable response. 3 Guinea-pig chroma n cells responded to ATP (100 mM) with a rapidly activating inward current. The amplitude of the response to ATP increased over the period cells were maintained in culture and so did the number of cells giving a detectable response, with 69% of cells responding after 54 days of culture. 4 The response to ATP desensitized slowly, and had a reversal potential of 2.5 mV. The EC 50 for ATP was 43 mM. The potency order for ATP analogues was 2-MeSATP4ATP4ADP. Adenosine, UTP and a,b-meATP were inactive. 5 Suramin (100 mM) and Cibacron blue (50 mM) inhibited the ATP (100 mM)-activated current by 51 and 47%, respectively. PPADS antagonized the response to ATP (100 mM) with an IC 50 of 3.2 mM. 6 The ATP concentration-response curve shifted to the left at pH 6.8 (EC 50 , 19 mM) and right at pH 8.0 (EC 50 , 96 mM), without changing the maximal response. Zn 2+ inhibited the response to ATP (100 mM) with an IC 50 of 48 mM. 7 This study indicates that expression of ATP-gated cation channels in chroma n cells is species dependent. The P2X receptors in guinea-pig chroma n cells show many characteristics of the P2X 2 receptor subtype.

show abstract

Section: Methodsmentioning

confidence: 99%

Rat chromaffin cells lack P2X receptors while those of the guinea‐pig express a P2X receptor with novel pharmacology

Liu

Dunn

King

et al. 1999

British J Pharmacology

View full text Add to dashboard Cite

show abstract

“…In some experiments, agonists were applied rapidly by use of a solenoid valvecontrolled U‐tube system placed very near the cell (Krishtal & Pidoplichko, 1980). In other experiments where antagonists were used, drugs were applied rapidly through a seven‐barrel manifold composed of fused glass capillaries inserted into a common outlet tube with a tip diameter of ∼200 μ m (Dunn et al , 1996). Solutions were delivered by gravity flow from independent reservoirs placed above the preparation.…”

Section: Methodsmentioning

confidence: 99%

Pharmacological and molecular characterization of P2X receptors in rat pelvic ganglion neurons

Zhong

Dunn

Xiang

et al. 1998

British J Pharmacology

View full text Add to dashboard Cite

1 The presence and characteristics of P2X receptors on neurons of the rat major pelvic ganglia (MPG) have been studied using whole cell voltage-clamp, in situ hybridization and immunohistochemistry. 2 Rapid application of ATP (100 mM) to isolated rat MPG neurons induced moderately large inward currents (0.33 ± 5.3 nA) in 39% of cells (108/277). The response to ATP occurred very rapidly, with an increase in membrane conductance, and desensitized slowly. 3 The concentration-response curve for ATP yielded an EC 50 of 58.9 mM. The agonist pro®le was ATP52MeSATP=ATPgS4BzATP, while a,b-MeATP, b,g-MeATP, UTP and ADP were all inactive at concentrations up to 100 mM. 4 The response to ATP was antagonized by suramin (pA 2 =5.6), reactive blue-2 (IC 50 =0.7 mM) and pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS). 5 Lowering the pH from 7.4 to 6.8 produced a marked potentiation (to 339% of control) of the responses to ATP (30 mM), while raising the pH to 8.0 attenuated the responses (to 20% of control). The EC 50 s for ATP were 28.8, 58.9 and 264 mM at pH 6.8, 7.4 and 8.0, respectively. 6 Co-application of ATP with Zn 2+ produced a marked enhancement of the responses to ATP, with an EC 50 of 9.55 mM. In the presence of Zn 2+ (30 mM), the EC 50 for ATP was decreased to 4.57 mM. 7 In situ hybridization revealed that the P2X receptor transcripts levels in rat MPG neurons are P2X 2 4P2X 4 4P2X 1 , P2X 3 , P2X 5 and P2X 6 . The immunohistochemical staining revealed a small number of neurons with strong P2X 2 immunoreactivity. 8 In conclusion, our results indicate that there are P2X receptors present on MPG neurons. The pharmacological characteristics of these receptors, the in situ hybridization and immunohistochemical evidence are consistent with them being of the P2X 2 subtype, or heteromultimers, with P2X 2 being the dominant component.

show abstract

“…Culture dishes were placed on the stage of an inverted microscope (Diaphot, Nikon), and cells were visualized under phase contrast at x600 magnification. Culture dishes were perfused with extracellular solution at room temperature, at a rate of 0.5 ml/min, while solution was applied locally to the cell of interest using a microperfusion device (36). Recordings were carried out using the conventional whole cell patch clamp technique (37) or the perforated patch technique.…”

Section: Electrophysiologymentioning

confidence: 99%

Purinoceptor expression in regenerating skeletal muscle in the mdx mouse model of muscular dystrophy and in satellite cell cultures

et al. 2004

View full text Add to dashboard Cite

ATP is an important extracellular signaling molecule mediating its effects by activation of P2X and P2Y receptors. P2 receptors are expressed during muscle development, and recent findings demonstrate that ATP can regulate myoblast proliferation and differentiation in vitro. However, the role of purinergic signaling during regeneration of injured skeletal muscle has not been investigated. To examine this process in a clinically relevant system, we used the mouse model of muscular dystrophy (mdx), in which muscle degeneration is rapidly followed by regeneration. The latter process, in vivo muscle regeneration, was the focus of this study, and to study the cellular mechanisms involved in it, a parallel study on normal rat skeletal myoblast cultures was conducted. Using immunohistochemistry, RT-PCR, and electrophysiology, we investigated the expression of the P2X1-7 receptor subtypes and the P2Y1,2,4,6 receptors. Experiments in vitro and in vivo demonstrated the sequential expression of the P2X5, P2Y1, and P2X2 receptors during the process of muscle regeneration. The P2X5 and P2Y1 receptors were expressed first on activated satellite cells, and the P2Y1 receptor was also expressed on infiltrating immune cells. Subsequent P2X2 receptor expression on newly formed myotubes showed significant colocalization with AChRs, suggesting a role in regulation of muscle innervation. Thus, this study provides the first evidence for a role for purinergic signaling in muscle regeneration and raises the possibility of new therapeutic strategies in the treatment of muscle disease.

show abstract

Discrimination between subtypes of apamin‐sensitive Ca²⁺‐ activated K⁺ channels by gallamine and a novel bis‐quaternary quinolinium cyclophane, UCL 1530

Cited by 44 publications

References 34 publications

Rat chromaffin cells lack P2X receptors while those of the guinea‐pig express a P2X receptor with novel pharmacology

Rat chromaffin cells lack P2X receptors while those of the guinea‐pig express a P2X receptor with novel pharmacology

Pharmacological and molecular characterization of P2X receptors in rat pelvic ganglion neurons

Purinoceptor expression in regenerating skeletal muscle in the mdx mouse model of muscular dystrophy and in satellite cell cultures

Contact Info

Product

Resources

About