| RESEARCH PAPER |
|
| Year : 1989 | Volume
: 21
| Issue : 4 | Page : 111-119 |
Investigation of ethinyl estradiol induced potentiation of noradrenaline responses in isolated rat vas deferens
JD Bhatt, OD Gulati
Correspondence Address:
J D Bhatt
 Source of Support: None, Conflict of Interest: None  | Check |
1. The effects of acute in vitro exposure of rat isolated vas deferens to ethinyl estradiol (EE; 1.01 x 10-5M) on the contractile responses to various agonists were investigated.
2. EE increased the pD2 values of noradrenaline (NE) and phenylephrine (PE); the pD2 values of methoxamine (MTX), and acetylcholine (ACh) were unaltered.
3. Pretreatment of vas deferens with neuronal uptake blocker, cocaine (1 x 10-5M) and also its denervation abolished the potentiating effect of EE on NA responses.
4. Pretreatment with extraneuronal uptake blocker, normetanephrine (1.2 x 10-5M) or monoamine oxidase (MAO) inhibitor, nialamide (3.35 x 10-5M) or catechol-O-methyl transferase (COMT) inhibitor tropolone (2 x l0-6M) or NE+-K+ ATPase inhibitor, digoxin (3.2 x l0-6GM) did not modify the potentiating effect of EE on NE response.
5, Combined treatment with normetanephrine (1.2 x l0-5M) pargyline (5.2 x l0-6M) and tropolone (2 x 10-6M) did not alter the potentiating effect. However, combined treatment with cocaine (1x 10-5M), normetanephrine (I .2 x 10-5), pargyline (5.2 x 10-5M) and tropolone (2 x 10-6M) abolished the potentiating effect.
6. It is concluded that in rat isolated vas deferens EE, specifically potentiated the contractile responses to certain alpha-adrenoceptor agonists, especially NE. which may be due to its neuronal uptake blocking property.
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