Pharmacological investigations on the regulation mechanisms of the periodic activity of the fresh water mussel (Anodonta cygnea L.)

Hiripi, László (1973) Pharmacological investigations on the regulation mechanisms of the periodic activity of the fresh water mussel (Anodonta cygnea L.). A Magyar Tudományos Akadémia Tihanyi Biológiai Kutatóintézetének évkönyve, 40. pp. 27-53. ISSN 0365-3005

Preview

Text 28_cut_MTA_TihanyiBiologiaiKutIntEvkonyve_40.pdf Download (16MB) | Preview

Abstract

On the basis of an earlier working hypothesis we investigated whether the pharmacological influences on the transmitter systems of the assumed centres of “activity ” and “rest” responsible for the regulation of the rhythm of fresh water mussel (Anodonta cygnea L.) act on the monoamine levels and the periodicity of the activity. The serotoninergic system of the centre of activity was influenced by inhibition of synthesis (pCPA) and the inactivating enzyme (tranylcypromine) by depletion of 5HT (Reserpine, V-111) as well as by exogeneous 5HT. The catecholaminergic system of the centre of rest was altered by exogeneous dopamine and noradrenaline, a-methyl-metatyrosine, reserpine and tranylcypromine. Investigating the periodic activity and the monoamine levels, it was found: 1. The 5HT level plays a decisive role in the function of the centre of activity. The prolonged activity caused by exogeneous 5HT is a consequence of prolonged increase of 5HT level, manifesting itself primarily in the increase of th eaverage length of active periods. 2. The ganglionic 5HT level was not increased by the MAO-inhibiting tranylcypromine, however, prolonged active periods and great increase of rhythmic contractions were induced by this drug through the absence of the peripheric inactivation. After the treatment the frequency of rhythmicity was increased by decreasing the average lengths of active and rest periods. 3. The decrease of 5HT level caused by pCPA and reserpine, resulted in the decrease of average length of active periods and the increase of that of the rest ones. The p-brom-metamphetamine increases mainly the frequency of rhythmicity through a slight decrease of 5HT level. 4. The dopamine decreases the average length of both the active and rest periods, whereas the noradrenaline increases that of the inactive ones. The effect of α-MMT is probably realized through the effect of NA and the significant increase of the rest periods is caused by the liberation of NA. 5. After reserpine treatment the predominance of the centre of rest is induced partly by the significant decrease of 5HT level and partly by the considerable NA level persisting because of the slower depletion of NA. 6. The 5HT level in itself cannot determine the function of the centre of activity. The active transport toward the adductors takes also part in the relaxation of the adductors, i.e. in the regulation of the active period. The decrease of 5HT level influences the active transport only below a certain critical level.

Actions (login required)

Edit Item