ThePulmonaria dacica group: Its affinities with central and south-east European allies and with the genusParaskevia (Boraginaceae)

Comparative morphological, karyological and chorological studies prove the distinctness of the SE European and Asiatic populations ofPulmonaria mollis s.l., to be treated asP. dacica (Figs. 4, 5).P. mollis s.str. is interpreted as a relatively young taxon, which probably has evolved from an older stock ofP. dacica ancestors during the Pleistocene (Figs. 6, 8) and might have migrated, perhaps with oak woodland communities, from SE to C. Europe. A similar evolution can be postulated for S—SE European dysploidP. rubra-carnica-stiriaca-vallarsae group; this may have involved still unknown tetraploids (P. carnica?, Fig. 7). This group is linked via the hypertriploid speciesP. vallarsae with theP. saccharata group and at least the eastern species of theP. australis group. The monotypic genusParaskevia apparently marks the earliest divergence from the common Tertiary ancestral stock (Fig. 8). It exhibits a tetraploid chromosome number (2n = 28) but has preserved the most primitive characters. — Some comments on the systematics and nomenclature ofP. australis andParaskevia are added.     

下丘脑前区的脑啡肽参与急性心肌缺血减弱颈动脉窦升压反射的效应

家兔急性心肌缺血时,下丘脑等脑区亮啡肽(L-Enk)含量显著升高,延脑未见明显变化,向下丘脑前区直接注射微量L-Enk,同阻断冠脉效应相同,也可减弱窦升压反射。该区注射纳络酮(Nx)可逆转心肌缺血减弱窦升压反射的效应,而对正常兔的窦升压反射没有明显影响。提示:急性心肌缺血时,下丘脑前区的脑啡肽可被激活,并参与窦升压反射的调节。但在正常情况下,这些脑啡肽可能处在非活动状态,在窦升压反射的调节中可能不起重要作用。     

Membrane-Bound and cytosolic forms of heterotrimeric G proteins in young and adult rat myocardium: influence of neonatal hypo- and hyperthyroidism.

Membrane and cytosolic fractions prepared from ventricular myocardium of young (21-day-old) hypo- or hyperthyroid rats and adult (84-day-old) previously hypo- or hyperthyroid rats were analyzed by immunoblotting with specific anti-G-protein antibodies for the relative content of Gs alpha, Gi alpha/Go alpha, Gq alpha/G11 alpha, and G beta. All tested G protein subunits were present not only in myocardial membranes but were at least partially distributed in the cytosol, except for Go alpha2, and G11 alpha. Cytosolic forms of the individual G proteins represented about 5-60% of total cellular amounts of these proteins. The long (Gs alpha-L) isoform of Gs alpha prevailed over the short (Gs alpha-S) isoform in both crude myocardial membranes and cytosol. The Gs alpha-L/Gs alpha-S ratio in membranes as well as in cytosol increased during maturation due to a substantial increase in Gs alpha-L. Interestingly, whereas the amount of membrane-bound Gi alpha/Go alpha and Gq alpha/G11 alpha proteins tend to lower during postnatal development, cytosolic forms of these G proteins mostly rise. Neonatal hypothyroidism reduced the amount of myocardial Gs alpha and increased that of Gi alpha/Go alpha proteins. By contrast, neonatal hyperthyroidism increased expression of Gs alpha and decreased that of Gi alpha and G11 alpha in young myocardium. Changes in G protein content induced by neonatal hypo- and hyperthyroidism in young rat myocardium were restored in adulthood. Alterations in the membrane-cytosol balance of G protein subunits associated with maturation or induced by altered thyroid status indicate physiological importance of cytosolic forms of these proteins in the rat myocardium.