Cardiac fibrosis is one of the deleterious events accompanying hypertension that may be implicated in the progression toward heart failure. To determine the mechanisms involved in fibrosis and the role of hemodynamic versus humoral factors, we studied the expression of genes involved in hypertrophy and fibrosis in the heart of rats treated with aldosterone for 2 months with addition of 1% NaCl and 0.3% KC1 in water. This treatment induced arterial hypertension, a moderate left ventricular hypertrophy, and a decrease in plasma thyroxine. Equatorial sections of hearts from treated rats showed numerous foci of proliferating nonmuscular cells and a biventricular fibrosis. Computerized videodensitometry demonstrated an increase of collagen volume fraction by 152% and 146% and of the ratio of the perivascular collagen area and vascular area by 86% and 167% in left and right ventricles,

The energetics of the senescent (S) rat heart and the mechanisms by which it adapts to pressure overload have been investigated by simultaneous cardiac mechanical, energetic, and molecular biological studies. Compared with young adult (YA), S papillary muscles had an improved economy of contraction since the curvature (G) of Hill's (Proc. R. Soc. Lond. B. Biol. Sci. 126:136-195, 1938) hyperbola was increased (S, 1.93 +/- 0.13; YA, 1.60 +/- 0.07, P < 0.05). In addition, the maximum unloaded shortening (Vmax) and relengthening velocities were both reduced in S. In parallel, both alpha-myosin heavy chain (MHC) and sarcoplasmic reticulum (SR) Ca(2+)-adenosinetriphosphatase (ATPase) mRNA contents were reduced (-30 and -28%, respectively), whereas beta-MHC mRNA was increased (+91%). The active tension (S, 40.0 +/- 2.6; YA, 50.1 +/- 2.5 mN/mm2, P < 0.01) was depressed although the active force remained unchanged (S, 52.0 +/- 4.0; YA, 47.5 +/- 2.5 mN). Pressure overload in senescent deoxycorticosterone acetate (DOCA)-salt rats induced a left ventricular hypertrophy (+43%) and a further decrease in both Vmax (S, 2.81 +/- 0.10; DOCA-salt, 2.55 +/- 0.13 initial length corresponding to peak of length-active curve/s, P < 0.05) and alpha-MHC mRNA (-30%) content. Senescence modifies mechanics and gene expression in a way similar to pressure overload. During senescence, an additional overload induces left ventricular hypertrophy and attenuates Vmax without worsening the economy of the contraction.

Lupin is toxic because of its alkaloid content, sparteine and lupanine in particular. Although the pharmacological properties of sparteine are well known those of lupanine have not been much studied. This paper reports procedures for extraction, purification and crystallization of lupanine, and methods for the preparation of an extract for injection of Lupinus mutabilis Sweet, and for the determination of the acute toxicity and maximum non-lethal dose (DL0) of lupanine, sparteine and lupin extract in the mouse. The three substances were tested on the central nervous system (CNS) for locomotor activity, for interaction with specific drugs used for treatment of the CNS (the stimulant drugs amphetamine and pentetrazol and the depressant drugs pentobarbital and chlorpromazine) and for analgesic activity. The results indicate that lupanine and lupin extract are less toxic than sparteine and that at the doses studied the three products have a weak sedative effect on the CNS.