Abstract
1. The adrenergic receptors in the systemic vasculature of the rainbow trout have been pharmacologically characterized using an isolated trunk preparation perfused at constant flow. 2. The dominant α-constrictory receptors in the trunk are similar to those of mammals in their adrenaline/noradrenaline potency ratio (3.2/1.0), and in the natures of their blockade by phenoxybenzamine and yohimbine. However they are more selective than mammalian α-receptors, responding directly to only adrenaline and noradrenaline, and not to phenylephrine, methoxamine, dopamine, or isoprenaline. 3. Tyramine and dopamine cause weak α-adrenergic constriction, apparently indirectly through the release of catecholamine stores. 4. The α-adrenergic response is susceptible to inhibition by competitive β-blocking agents, but this effect is due to non-competitive antagonism with a point of action beyond the adrenergic receptor. 5. β-dilatory receptors of the β2, as in the homologous systemic vasculature of mammals, also apparently occur, but their dilatory actions cn only be demonstrated against a background of α-adrenergic vasoconstriction. 6. The racemate d,l-isoprenaline is a more potent vasodilator than the pure isomer l-isoprenaline during α-adrenergic tone because of the competitive α-blocking activity of the d-isomer.
| Original language | English |
|---|---|
| Pages (from-to) | 211-228 |
| Number of pages | 18 |
| Journal | Journal of Comparative Physiology ■ B |
| Volume | 107 |
| Issue number | 2 |
| DOIs | |
| State | Published - Jan 1 1976 |
Fingerprint
ASJC Scopus subject areas
- Physiology (medical)
- Environmental Science(all)
- Physiology
- Animal Science and Zoology
Cite this
Pharmacological properties of the adrenergic receptors regulating systemic vascular resistance in the rainbow trout. / Wood, Chris M.
In: Journal of Comparative Physiology ■ B, Vol. 107, No. 2, 01.01.1976, p. 211-228.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Pharmacological properties of the adrenergic receptors regulating systemic vascular resistance in the rainbow trout
AU - Wood, Chris M.
PY - 1976/1/1
Y1 - 1976/1/1
N2 - 1. The adrenergic receptors in the systemic vasculature of the rainbow trout have been pharmacologically characterized using an isolated trunk preparation perfused at constant flow. 2. The dominant α-constrictory receptors in the trunk are similar to those of mammals in their adrenaline/noradrenaline potency ratio (3.2/1.0), and in the natures of their blockade by phenoxybenzamine and yohimbine. However they are more selective than mammalian α-receptors, responding directly to only adrenaline and noradrenaline, and not to phenylephrine, methoxamine, dopamine, or isoprenaline. 3. Tyramine and dopamine cause weak α-adrenergic constriction, apparently indirectly through the release of catecholamine stores. 4. The α-adrenergic response is susceptible to inhibition by competitive β-blocking agents, but this effect is due to non-competitive antagonism with a point of action beyond the adrenergic receptor. 5. β-dilatory receptors of the β2, as in the homologous systemic vasculature of mammals, also apparently occur, but their dilatory actions cn only be demonstrated against a background of α-adrenergic vasoconstriction. 6. The racemate d,l-isoprenaline is a more potent vasodilator than the pure isomer l-isoprenaline during α-adrenergic tone because of the competitive α-blocking activity of the d-isomer.
AB - 1. The adrenergic receptors in the systemic vasculature of the rainbow trout have been pharmacologically characterized using an isolated trunk preparation perfused at constant flow. 2. The dominant α-constrictory receptors in the trunk are similar to those of mammals in their adrenaline/noradrenaline potency ratio (3.2/1.0), and in the natures of their blockade by phenoxybenzamine and yohimbine. However they are more selective than mammalian α-receptors, responding directly to only adrenaline and noradrenaline, and not to phenylephrine, methoxamine, dopamine, or isoprenaline. 3. Tyramine and dopamine cause weak α-adrenergic constriction, apparently indirectly through the release of catecholamine stores. 4. The α-adrenergic response is susceptible to inhibition by competitive β-blocking agents, but this effect is due to non-competitive antagonism with a point of action beyond the adrenergic receptor. 5. β-dilatory receptors of the β2, as in the homologous systemic vasculature of mammals, also apparently occur, but their dilatory actions cn only be demonstrated against a background of α-adrenergic vasoconstriction. 6. The racemate d,l-isoprenaline is a more potent vasodilator than the pure isomer l-isoprenaline during α-adrenergic tone because of the competitive α-blocking activity of the d-isomer.
UR - http://www.scopus.com/inward/record.url?scp=34250384510&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=34250384510&partnerID=8YFLogxK
U2 - 10.1007/BF00691227
DO - 10.1007/BF00691227
M3 - Article
AN - SCOPUS:34250384510
VL - 107
SP - 211
EP - 228
JO - Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology
JF - Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology
SN - 0174-1578
IS - 2
ER -