Abstract
The effects of racemic propranolol and its constituent isomers were studied on ganglionic stimulation produced in situ by close arterial injection of 5-HT and DMPP to the superior cervical ganglion. Ganglion stimulation was recorded in terms of the resultant contraction of the nictitating membrane. d,l-Propranolol caused a biphasic antagonism of the ganglion stimulant effect of 5-HT. At low doses, 0.5-10 μg, the antagonism was surmountable by increasing the amount of 5-HT. The l-isomer (0.2-4 μg) but not d-propranolol also caused antagonism. At higher doses, 0.1-5 mg, both d,l- and d-propranolol caused a second type of blockade of 5-HT which was not surmountable and resembled that seen with procaine. The ganglion stimulatn effects of DMPP and acetylcholine were only antagonised by the higher doses of d- and d,l-propranolol. d,l-Propranolol did not reduce the direct stimulation by 5-HT on the muscle of the nictitating membrane.
| Original language | English |
|---|---|
| Pages (from-to) | 293-301 |
| Number of pages | 9 |
| Journal | European Journal of Pharmacology |
| Volume | 32 |
| Issue number | 2 |
| DOIs | |
| State | Published - 1975 |
| Externally published | Yes |
Keywords
- 5-HT
- DMPP
- Non-specific antagonism
- Specific antagonism
- Superior cervical ganglion
- d,l-Propranolol
- d-Propranolol
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