Abstract
In order to ascertain the relative contribution of the endothelial and neuronal nitric oxide (NO) synthase isoforms on NO-dependent vascular and nerve function in vitro, aorta and corpus cavernosum from mice deficient in their expression (eNOS-/- and nNOS-/-) were isolated in organ baths for tension measurements. Agonist or electrical field stimulation (EFS) evoked nerve-mediated responses were compared against wild-type controls. In aortas from nNOS-/- mice, contraction responses to phenylephrine were increased. Conversely, endothelium-dependent relaxation (EDR) to acetylcholine (ACh) was decreased. In contrast, eNOS-/- aortas showed decreased sensitivity to phenylephrine and developed a flurbiprofen-sensitive contraction to ACh, and sensitivity to the NO-donor sodium nitroprusside was increased. In cavernosum from eNOS-/- and nNOS-/- mice, maximum contractions to phenylephrine and EFS, and relaxation responses to nitroprusside, were increased. As in aorta, ACh addition led to a contractile response in eNOS-/- cavernosum. Maximum EFS induced non-adrenergic, non-cholinergic (NANC) nerve-mediated relaxation was increased in eNOS-/-, whilst being decreased in nNOS-/- cavernosum. These data suggest that whilst NO-dependent vascular function is primarily eNOS mediated, and nerve function nNOS mediated, aorta function may be at least partially reliant on nNOS-related mechanisms. In addition, mechanisms of physiological compensation were observed, which require further study.
Original language | English |
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Pages (from-to) | 139-145 |
Number of pages | 6 |
Journal | Pflugers Archiv : European Journal of Physiology |
Volume | 448 |
Issue number | 2 |
DOIs | |
Publication status | Published - May 2004 |
Keywords
- aorta
- corpus cavernosum
- endothelium
- NANC nerve
- nitric oxide
- smooth muscle
- NITRIC-OXIDE SYNTHASE
- ACETYLCHOLINE-INDUCED RELAXATION
- KNOCKOUT MICE
- PENILE ERECTION
- LACKING
- RAT
- FLOW
- DILATION
- ARTERIES
- MOUSE