Abstract
1. Cholinergic mechanisms in the systemic vasculature of the rainbow trout have been pharmacologically analysed using an isolated trunk preparation perfused at constant flow. 2. Acetylcholine (ACh) causes a two component vasoconstriction comprising a rapid initial peak (response A) and a long-lasting tail on the initial peak (response B). Skeletal muscle contraction is not involved in either response. 3. Response B has a high dose threshold, is nicotinic in nature, and is blocked by α-adrenoreceptor antagonists, procaine, and 0 mM Ca++ plus 20 mM Mg++, indicating a classical indirect action of ACh on sympathetic neurons or chromaffin tissue to cause the release of an adrenergic transmitter. 4. Response A has a lower dose threshold, is nicotinic in nature, is resistant to α-adrenergic, muscarinic cholinergic, and adrenergic neuron blockade, is insensitive to tetrotoxin and 0 mM Ca++ plus 20 mM Mg++, but is blocked with some specificity by procaine. 5. The properties of the nicotinic receptors of response A differ from those of the traditional ganglionic and skeletal muscle types of higher vertebrates. 6. Response A is mimicked by ATP, which appears to act by a direct mechanism in the preparation. 7. It is concluded that response A reflects either direct stimulation of nicotinic receptors on vascular tissue or an indirect nicotinic effect resulting in the release of a non-adrenergic, non-cholinergic transmitter such as ATP. 8. Unlike the situation in higher vertebrates, no muscarinic dilatory responses to ACh occur in the preparation.
| Original language | English |
|---|---|
| Pages (from-to) | 325-345 |
| Number of pages | 21 |
| Journal | Journal of Comparative Physiology ■ B |
| Volume | 122 |
| Issue number | 3 |
| DOIs | |
| State | Published - Jan 1 1977 |
Fingerprint
ASJC Scopus subject areas
- Physiology (medical)
- Environmental Science(all)
- Physiology
- Animal Science and Zoology
Cite this
Cholinergic mechanisms and the response to ATP in the systemic vasculature of the rainbow trout. / Wood, Chris M.
In: Journal of Comparative Physiology ■ B, Vol. 122, No. 3, 01.01.1977, p. 325-345.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Cholinergic mechanisms and the response to ATP in the systemic vasculature of the rainbow trout
AU - Wood, Chris M.
PY - 1977/1/1
Y1 - 1977/1/1
N2 - 1. Cholinergic mechanisms in the systemic vasculature of the rainbow trout have been pharmacologically analysed using an isolated trunk preparation perfused at constant flow. 2. Acetylcholine (ACh) causes a two component vasoconstriction comprising a rapid initial peak (response A) and a long-lasting tail on the initial peak (response B). Skeletal muscle contraction is not involved in either response. 3. Response B has a high dose threshold, is nicotinic in nature, and is blocked by α-adrenoreceptor antagonists, procaine, and 0 mM Ca++ plus 20 mM Mg++, indicating a classical indirect action of ACh on sympathetic neurons or chromaffin tissue to cause the release of an adrenergic transmitter. 4. Response A has a lower dose threshold, is nicotinic in nature, is resistant to α-adrenergic, muscarinic cholinergic, and adrenergic neuron blockade, is insensitive to tetrotoxin and 0 mM Ca++ plus 20 mM Mg++, but is blocked with some specificity by procaine. 5. The properties of the nicotinic receptors of response A differ from those of the traditional ganglionic and skeletal muscle types of higher vertebrates. 6. Response A is mimicked by ATP, which appears to act by a direct mechanism in the preparation. 7. It is concluded that response A reflects either direct stimulation of nicotinic receptors on vascular tissue or an indirect nicotinic effect resulting in the release of a non-adrenergic, non-cholinergic transmitter such as ATP. 8. Unlike the situation in higher vertebrates, no muscarinic dilatory responses to ACh occur in the preparation.
AB - 1. Cholinergic mechanisms in the systemic vasculature of the rainbow trout have been pharmacologically analysed using an isolated trunk preparation perfused at constant flow. 2. Acetylcholine (ACh) causes a two component vasoconstriction comprising a rapid initial peak (response A) and a long-lasting tail on the initial peak (response B). Skeletal muscle contraction is not involved in either response. 3. Response B has a high dose threshold, is nicotinic in nature, and is blocked by α-adrenoreceptor antagonists, procaine, and 0 mM Ca++ plus 20 mM Mg++, indicating a classical indirect action of ACh on sympathetic neurons or chromaffin tissue to cause the release of an adrenergic transmitter. 4. Response A has a lower dose threshold, is nicotinic in nature, is resistant to α-adrenergic, muscarinic cholinergic, and adrenergic neuron blockade, is insensitive to tetrotoxin and 0 mM Ca++ plus 20 mM Mg++, but is blocked with some specificity by procaine. 5. The properties of the nicotinic receptors of response A differ from those of the traditional ganglionic and skeletal muscle types of higher vertebrates. 6. Response A is mimicked by ATP, which appears to act by a direct mechanism in the preparation. 7. It is concluded that response A reflects either direct stimulation of nicotinic receptors on vascular tissue or an indirect nicotinic effect resulting in the release of a non-adrenergic, non-cholinergic transmitter such as ATP. 8. Unlike the situation in higher vertebrates, no muscarinic dilatory responses to ACh occur in the preparation.
UR - http://www.scopus.com/inward/record.url?scp=9044238716&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=9044238716&partnerID=8YFLogxK
U2 - 10.1007/BF00692519
DO - 10.1007/BF00692519
M3 - Article
AN - SCOPUS:9044238716
VL - 122
SP - 325
EP - 345
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 - 3
ER -