[Change in intensity of respiration in development of some invertebrates]. / Izmenenie intensivnosti dykhaniia v ontogeneze nekotorykh bespozvonochnykh.

We studied the dynamic of respiration intensity during ontogenesis of flat worms (Dugesia tigrina), molluscs (Anodonta piscinalis and Viviparus viviparus, and insects (Leptinotarsa decemlineata). In planarians that reproduce vegetatively, the intensity of respiration increases just after fission and decreases at the subsequent phases of growth. In A. piscinalis, this index of metabolism increases during embryonic and early larval development and decreases at the later developmental stages. In V. viviparus, which develops in the female genital tract, the intensity of respiration remains unchanged during embryogenesis and decreases during late embryogenesis and subsequent phases of growth. In L. decemlineata, the intensity of respiration increases during embryonic and early larval development and then decreases to undergo cyclic changes times to molts. This index markedly decreases in the pupae, increases in the beginning of imaginal period, and then again decreases.

[Seasonal changes in myocardial sensitivity to acetylcholine in the molluscs, Anodonta complanata and Anodonta piscinalis]. / Sezonnye izmeneniia chuvstvitel'nosti k atsetilkholinu serdechnoi myshtsy molliuskov Anodonta complanata i Anodonta piscinalis.

Seasonal changes in ACh sensitivity have been studied on isolated cardiac muscle of the bivalve molluscs together with ATP content of the hemolymph and the heart. The lowest ACh sensitivity of the heart was found in August and October (KACh in August was equal to 44.0.10(-6) M). Maximum sensitivity was observed in March and at the end of August--the beginning of September (KACh in March was equal to 1.27 X X 10(-6) M); at this period of year, ATP content of the hemolymph decreases approximately 100-fold, the release of ATP from the heart in the presence of ACh being also decreased. Maximum level of ATP in cardiac muscle was found in July. It was demonstrated that most significant changes in ACh sensitivity take place during spawning, especially when sex cells are transported from the gonads into the gills, as well as during the release of glochidia from the latter. Possible causes of seasonal changes in ACh sensitivity of cardiac muscle and the role of ATP in this process are discussed.