Pharmacological properties of the heart of Tyumbricus terrestris L.

S.-Rózsa, Katalin and V.-Szőke, Ida (1970) Pharmacological properties of the heart of Tyumbricus terrestris L. A Magyar Tudományos Akadémia Tihanyi Biológiai Kutatóintézetének évkönyve, 37. pp. 85-97. ISSN 0365-3005

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Abstract

1. The frequency of contractions of the blood vessels of Lumbricus terrestris L. showed seasonal variations. In autumn the number of heart contractions per minute was found to be 16-32, while in winter this number was 45-75. 2. Of the biologically active agents tested acetylcholine (10⁻¹⁰M), adrenaline (10⁻¹⁰M), noradrenaline (10⁻¹⁰M) and trvptamine (10⁻⁹M) increase the heart rate of Lumbricus, while dopamine (10⁻⁵M), isopropylnoradrenaline (10⁻⁶M), 5-hydroxytryptamine (10⁻⁷M) and GABA (10⁻⁷M) have a decreasing effect on heart activity. Histamine and tyramine have a double effect. 3. Acetylcholine, adrenaline and noradrenaline may act as stimulatory mediators, while 5-hydroxytryptamine and GABA may play the role of inhibitory mediators on the heart of Lumbricus. 4. Nicotine, DCI and mytolon, similarly to acetylcholine and adrenaline, produce acceleration of heart rate in Lumbricus, while BOL-148 and methysergide have an inhibitory effect. 5. On the heart of Lumbricus the effects of monoamines, ACh and GABA take place on mixed receptor structures which differ from receptors of other animal groups. 6. Concerning pharmacological sensitivity, the Lumbricus heart seems to be related to the neurogenic hearts of Arthropods and not to myogenic hearts of Molluscs and vertebrates. As to the effect of acetylcholine, the Lumbricus heart seems to stand near the insect heart, whereas on the basis of its response to GABA it seems to be nearer to the Crustacean heart.

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