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Substance P as a transmitter in the human ciliary muscle
1Department of Pharmaco-Biology, University of Bari, Italy.
Pharmacological Research Communications
|October 1, 1988
Summary
Substance P acts as an excitatory transmitter in human ciliary muscle contractions. Blocking its effects with a synthetic analogue, (D-Pro2-D-Trp7,9)-SP, abolished contractions resistant to other blockers.
Area of Science:
- Ophthalmology
- Neuroscience
- Pharmacology
Background:
- The human ciliary muscle is crucial for accommodation.
- The role of neurotransmitters in ciliary muscle contraction is not fully understood.
- Substance P is a neuropeptide with diverse physiological functions.
Purpose of the Study:
- To investigate the involvement of substance P as an excitatory transmitter in human ciliary muscle.
- To characterize the effects of substance P on ciliary muscle contraction.
Main Methods:
- Experiments were conducted on fresh human ciliary muscle tissue.
- Cholinergic and adrenergic pathways were blocked pharmacologically.
- The effect of a substance P antagonist, (D-Pro2-D-Trp7,9)-SP, on electrically stimulated contractions was assessed.
- The effects of exogenous substance P were also investigated.
Main Results:
- A resistant component of contraction, not affected by cholinergic or adrenergic blockade, was identified.
- (D-Pro2-D-Trp7,9)-SP completely abolished this resistant contraction.
- Exogenous substance P was shown to have effects on the ciliary muscle.
Conclusions:
- Substance P is implicated as an excitatory neurotransmitter in the human ciliary muscle.
- Targeting substance P may offer a novel therapeutic approach for modulating ciliary muscle function.