Effects of cooling and ARL 67156 on synaptic ecto-ATPase activity in guinea pig and mouse vas deferens

Ghildyal, P.; Manchanda, Rohit

doi:10.1016/j.autneu.2004.07.005

Cited by 8 publications

(17 citation statements)

References 33 publications

(41 reference statements)

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“…Degradation by the putative released ATPases has been reported to be temperature independent, 28 which contrasts with the temperature-dependent degradation observed in the present study. The temperature dependency of ATP degradation by an ecto-enzymatic system was also shown for mouse and guinea-pig vas deferens 20 and, therefore, the present results confirm the involvement of ecto-enzymes in the degradation of extracellular purines in the rat vas deferens.…”

Section: Discussionsupporting

confidence: 86%

“…The effects of the 5′‐nucleotidase inhibitor α,β‐methylene‐ADP (10 µmol/L 18 ) and of the alkaline phosphatase inhibitors levamisole (10 mmol/L 19 ) and β‐glycerophosphate (10 mmol/L 19,20 ) on ‘300 nmol/L ε‐AMP’ degradation are shown in Fig. 4.…”

Section: Resultsmentioning

confidence: 99%

“…24 In the rat vas deferens, the involvement of ecto-nucleotidases in ATP degradation has been demonstrated 25,26 and seems to occur in the vasa deferentia of the mouse 20 and of guinea-pig. 20,27 The degradation of ATP by extracellular enzymes has been proposed to also occur by released ATPases. 28 Because in the present study the incubation was performed in the absence of nervous stimulation, it is unlikely that released ATPases are involved in the degradation of ⑀-ATP observed under the present experimental conditions.…”

Section: Discussionmentioning

confidence: 98%

“…A sequential degradation of ATP by ecto‐nucleotidases (ecto‐ATPase, ecto‐apyrase, ecto‐ADPase and ecto‐5′‐nucleotidase) has been proposed for the removal of extracellular purines 24 . In the rat vas deferens, the involvement of ecto‐nucleotidases in ATP degradation has been demonstrated 25,26 and seems to occur in the vasa deferentia of the mouse 20 and of guinea‐pig 20,27 …”

Section: Discussionmentioning

confidence: 99%

“…Alkaline phosphatase, an enzyme able to use AMP as a substrate and subsequently form adenosine, 19 may be a possibility. Involvement of alkaline phosphatase is supported not only by the increase in the degree of AMP degradation caused by the increase in pH from 7.4 to 8.5, but also by the inhibition of AMP degradation caused by levamisole and by β‐glycerophosphate, drugs reported to affect the activity of this enzyme 19,20 …”

Section: Discussionmentioning

confidence: 99%

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Regional Differences in Extracellular Purine Degradation in the Prostatic and Epididymal Portions of the Rat Vas Deferens

Diniz

Fresco

Gonçalves

2005

Clin Exp Pharma Physio

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1. The aim of the present study was to compare ecto-nucleotidase activities in rat bisected vas deferens using 1,N6-etheno(epsilon)-nucleotides (epsilon-ATP and epsilon-AMP) as substrates. Degradation was estimated by measuring the disappearance of the substrate and the appearance of its metabolites using HPLC with fluorescence detection. Incubation of tissue preparations (prostatic or epididymal portions) with 300 nmol/L epsilon-ATP at 37 degrees C caused a partial disappearance of epsilon-ATP and appearance of its metabolites (epsilon-ADP, epsilon-AMP and epsilon-adenosine). Incubation at 25 degrees C reduced epsilon-ATP degradation more in the prostatic than in the epididymal portion. 2. Incubation of tissue preparations with epsilon-AMP at 37 degrees C resulted in the disappearance of epsilon-AMP and the appearance of epsilon-adenosine, which was more pronounced in the epididymal than in the prostatic portion. Incubation at 25 degrees C reduced epsilon-AMP degradation more in the epididymal than in the prostatic portion. 3. Decreasing pH from 7.4 to 6.5 enhanced epsilon-AMP degradation only in the prostatic portion, whereas increasing pH from 7.4 to 8.5 enhanced epsilon-AMP degradation in both portions, but more markedly in the epididymal portion. The alkaline phosphatase inhibitors levamisole (10 mmol/L) and beta-glycerophosphate (10 mmol/L) reduced epsilon-AMP degradation only in the epididymal portion. 4. In conclusion, the results of the present study are compatible with the presence, in the bisected rat vas deferens, of an ecto-nucleotidase system that is involved in the degradation of extracellular purines, which may differ between the epididymal and prostatic portions, with the epididymal portion presenting a different and higher capacity to form adenosine.

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Section: Discussionsupporting

confidence: 86%