Pharmacology of the myogenic heart of the pond snail Lymnaea stagnalis
| Autor: | N. N. Osborne, G. J. Dockray, Paul R. Benjamin, K. J. Buckett |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Serotonin
Invertebrate Hormones Physiology Dopamine Radioimmunoassay Lymnaea stagnalis Substance P Pharmacology Inhibitory postsynaptic potential chemistry.chemical_compound medicine Animals FMRFamide Neurotransmitter Chromatography High Pressure Liquid Lymnaea Neurotransmitter Agents biology Chemistry General Neuroscience Neuropeptides Heart biology.organism_classification Immunohistochemistry Cinanserin Excitatory postsynaptic potential medicine.drug |
| Zdroj: | Journal of Neurophysiology. 63:1413-1425 |
| ISSN: | 1522-1598 0022-3077 |
| DOI: | 10.1152/jn.1990.63.6.1413 |
| Popis: | 1. We have used pharmacologic, immunologic, and biochemical techniques to examine the role of neurochemicals in modulating the myogenic heart of the snail, Lymnaea. 2. 5-HT [high-pressure liquid chromatography (HPLC) and immunocytochemistry], dopamine (HPLC), FMRFamide-related peptides (radioimmunoassay and immunocytochemistry) and substance P-related peptides (immunocytochemistry) were shown to be localized within heart tissue. 3. The pharmacologic actions of these substances on the auricle from an isolated heart preparation were examined together with other putative modulators, acetylcholine (ACh), small cardioactive peptides A and B (SCPA and SCPB), [Arg]8vasotocin (AVT), and Lymnaea native FMRFamide-related peptides [Phe-Met-Arg-Phe-NH2 (FMRFamide), Ser-Asp-Pro-Phe-Leu-Arg-Phe-NH2 (SDPFLRFamide) and Gly-Asp-Pro-Phe-Leu-Arg-Phe-NH2 (GDPFLRFamide)]. 4. The response to each substance could be distinguished by different effect on beat rate, amplitude, and diastolic tonus, as well as by the duration of responses to standard 1-min applications. ACh was inhibitory at low concentrations (threshold less than 10(-10) M) but excitatory at high concentrations (10(-6) M). AVT was alone in producing no dose-dependent response. At high concentrations (10(-4) M), AVT caused a massive tonic contraction and cessation of auricle beat. All other substances examined were excitatory. 5. Antagonists to 5-HT (cinanserin), dopamine (ergonovine), and ACh (alpha-bungarotoxin) were identified. 6. ACh, 5-HT, dopamine, and FMRFamide-related peptides all acted on the auricle at low concentrations, and the rapid onset and short duration of their excitatory effects (ACh inhibitory at low concentrations) suggested that they may have roles as neurotransmitters. SCPA and SCPB were also potent (threshold less than 10(-10) M) but produced long-duration responses suggesting a modulatory or hormonal role. |
| Databáze: | OpenAIRE |
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