Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:3.1.4.1 (
phosphodiesterase
)
18,767
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
The relaxant effects of nitroglycerin (NTG) and
SIN1
on human vena saphena magna were studied in vitro. Nitrate tolerance was produced after incubation of the preparation with nitroglycerin (NTG 10 microM for 10 minutes). Vessels precontracted by serotonin (0.25 microM) and made tolerant to NTG exhibited a slight but significant shift (p less than 0.01) to the right of the dose-response curve to
SIN1
(EC50 increased from 1.12 +/- 0.21 microM to 2.74 +/- 0.32 microM). The maximal relaxation was unaltered. On the contrary, there was a marked attenuation of the maximal relaxation to NTG in the nitrate-tolerant preparation (maximal relaxation decreased from 73 +/- 2% to 35 +/- 1%). Dipyridamole, a
phosphodiesterase
(PDe) inhibitor, significantly potentiated the responses to
SIN1
on control rings (EC50 = 57.1 +/- 1.8 nM), and on NTG-tolerant rings it reversed the responsiveness to
SIN1
(EC50 = 88.9 +/- 9.2 nM), which suggests that nitrate tolerance may be partially due to an increase in PDe activity. In conclusion we have demonstrated a slight cross-tolerance between
SIN1
and NTG on human vena saphena magna. Nevertheless, after induction of in vitro NTG tolerance, the attenuation of responses to
SIN1
is much less pronounced that the alteration of NTG relaxations.
...
PMID:Effect of nitrate tolerance and dipyridamole on the response to SIN1 in the human isolated saphenous vein. 190 34
