Abstract
1. The interaction of isoxuprine and nylidrin with α1- and β2-adrenoreceptors in rat vas deferens was examined using radioligand binding assays and physiological studies in vitro. 2. Isoxuprine and nylidrin have a greater affinity for binding to α1 (isoxuprine K(D) = 59 ± 15 nM; nylidrin K(D) = 41 ± 3 nM) than β2-(isoxuprine K(D) = 3,900 ± 500 nM; nylidrin K(D) = 900 ± 50 nM) adrenoreceptors in rat vas deferens. 3. Vas deferens from rats pretreated for 16-24 h with reserpine (3 mg/kg i.p.) were exposed to 10 μM phenoxybenzamine for 15 min to inactivate α-adrenoreceptors. Under these conditions high concentrations of both isoxuprine and nylidrin relaxed vas deferens contracted with 55 mM K+, however the relaxation was not blocked by the β-adrenoreceptor antagonist propranolol (10 μM). 4. Both isoxuprine and nylidrin were potent competitive antagonists of α1-adrenoreceptor mediated contraction of vas deferens. pA2 values for isoxuprine (6.9 ± .05) and nylidrin (7.1 ± .08) agreed well with K(D) values for binding to α1-adrenoreceptors in vas deferens. 5. The greater potency of isoxuprine and nylidrin in inhibiting α1-adrenoreceptors than binding to β2-adrenoreceptors or causing nonspecific relaxation suggest that α-adrenoreceptor antagonist actions of these drugs may be important in their ability to inhibit smooth muscle tone.
| Original language | English |
|---|---|
| Pages (from-to) | 213-219 |
| Number of pages | 7 |
| Journal | Journal of Autonomic Pharmacology |
| Volume | 5 |
| Issue number | 3 |
| State | Published - 1985 |
| Externally published | Yes |
Fingerprint
All Science Journal Classification (ASJC) codes
- Neuroscience(all)
- Pharmacology
Cite this
Effects of isoxuprine and nylidrin on adrenoreceptors in rat vas deferens. / Abel, Peter W.; Fox, A. W.; Minneman, K. P.
In: Journal of Autonomic Pharmacology, Vol. 5, No. 3, 1985, p. 213-219.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Effects of isoxuprine and nylidrin on adrenoreceptors in rat vas deferens
AU - Abel, Peter W.
AU - Fox, A. W.
AU - Minneman, K. P.
PY - 1985
Y1 - 1985
N2 - 1. The interaction of isoxuprine and nylidrin with α1- and β2-adrenoreceptors in rat vas deferens was examined using radioligand binding assays and physiological studies in vitro. 2. Isoxuprine and nylidrin have a greater affinity for binding to α1 (isoxuprine K(D) = 59 ± 15 nM; nylidrin K(D) = 41 ± 3 nM) than β2-(isoxuprine K(D) = 3,900 ± 500 nM; nylidrin K(D) = 900 ± 50 nM) adrenoreceptors in rat vas deferens. 3. Vas deferens from rats pretreated for 16-24 h with reserpine (3 mg/kg i.p.) were exposed to 10 μM phenoxybenzamine for 15 min to inactivate α-adrenoreceptors. Under these conditions high concentrations of both isoxuprine and nylidrin relaxed vas deferens contracted with 55 mM K+, however the relaxation was not blocked by the β-adrenoreceptor antagonist propranolol (10 μM). 4. Both isoxuprine and nylidrin were potent competitive antagonists of α1-adrenoreceptor mediated contraction of vas deferens. pA2 values for isoxuprine (6.9 ± .05) and nylidrin (7.1 ± .08) agreed well with K(D) values for binding to α1-adrenoreceptors in vas deferens. 5. The greater potency of isoxuprine and nylidrin in inhibiting α1-adrenoreceptors than binding to β2-adrenoreceptors or causing nonspecific relaxation suggest that α-adrenoreceptor antagonist actions of these drugs may be important in their ability to inhibit smooth muscle tone.
AB - 1. The interaction of isoxuprine and nylidrin with α1- and β2-adrenoreceptors in rat vas deferens was examined using radioligand binding assays and physiological studies in vitro. 2. Isoxuprine and nylidrin have a greater affinity for binding to α1 (isoxuprine K(D) = 59 ± 15 nM; nylidrin K(D) = 41 ± 3 nM) than β2-(isoxuprine K(D) = 3,900 ± 500 nM; nylidrin K(D) = 900 ± 50 nM) adrenoreceptors in rat vas deferens. 3. Vas deferens from rats pretreated for 16-24 h with reserpine (3 mg/kg i.p.) were exposed to 10 μM phenoxybenzamine for 15 min to inactivate α-adrenoreceptors. Under these conditions high concentrations of both isoxuprine and nylidrin relaxed vas deferens contracted with 55 mM K+, however the relaxation was not blocked by the β-adrenoreceptor antagonist propranolol (10 μM). 4. Both isoxuprine and nylidrin were potent competitive antagonists of α1-adrenoreceptor mediated contraction of vas deferens. pA2 values for isoxuprine (6.9 ± .05) and nylidrin (7.1 ± .08) agreed well with K(D) values for binding to α1-adrenoreceptors in vas deferens. 5. The greater potency of isoxuprine and nylidrin in inhibiting α1-adrenoreceptors than binding to β2-adrenoreceptors or causing nonspecific relaxation suggest that α-adrenoreceptor antagonist actions of these drugs may be important in their ability to inhibit smooth muscle tone.
UR - http://www.scopus.com/inward/record.url?scp=0022004299&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0022004299&partnerID=8YFLogxK
M3 - Article
C2 - 2997229
AN - SCOPUS:0022004299
VL - 5
SP - 213
EP - 219
JO - Autonomic and Autacoid Pharmacology
JF - Autonomic and Autacoid Pharmacology
SN - 1474-8665
IS - 3
ER -