Reproductive steroid receptors and actions in the locus coeruleus of male macaques: Part of an aggression circuit?

This study was initiated to determine whether the noradrenergic (NE) neurons of the locus coeruleus (LC) could mediate the stimulatory action of androgens on serotonin-related gene expression in male macaques. These experiments follow our observations that serotonin neurons lack androgen receptors (ARs), and yet respond to androgens. Male Japanese macaques (Macaca fuscata) were castrated for 5-7months and then treated for 3months with [1] placebo, [2] T (testosterone), [3] DHT (dihydrotestosterone; non-aromatizable androgen) plus ATD (steroidal aromatase inhibitor), or [4] FLUT (Flutamide; androgen antagonist) plus ATD (n=5/group).

Localization and regulation of reproductive steroid receptors in the raphe serotonin system of male macaques.

We previously showed that tryptophan hydroxylase 2 (TPH2) and serotonin reuptake transporter (SERT) mRNAs are increased by the androgens, testosterone (T) and dihydrotestosterone (DHT) in serotonin neurons of male macaques. In addition, we observed that serotonin in axons of a terminal region were markedly decreased by aromatase inhibition and lack of estradiol (E) from metabolism of T. These observations implicated androgen receptors (AR) and estrogen receptors (ER) in the transduction of steroid hormone actions in serotonin neurons.

Myocyte apoptosis during acute myocardial infarction in rats is related to early sarcolemmal translocation of annexin A5 in border zone.

Annexin A5 is a Ca2+-dependent phospholipid binding protein well known for its high phosphatidylserine affinity. In vitro, translocation to sarcolemma and externalization of endogenous annexin A5 in the cardiomyocyte has recently been demonstrated to exert a proapoptotic effect. To determine whether these in vitro findings occurred in vivo, we performed myocardial infarction (MI) and studied the time course of apoptosis and annexin A5 localization (0.

Externalization of endogenous annexin A5 participates in apoptosis of rat cardiomyocytes.

Objective: Annexins are Ca(2+)-dependent phospholipid binding proteins. Externalized annexin A5 has been recently suggested to have a proapoptotic effect. Our aim was to determine whether annexin A5, which is intracellular in cardiomyocytes, could be translocated and/or externalized and play a role during the apoptotic process.

Expression and localization of the annexins II, V, and VI in myocardium from patients with end-stage heart failure.

Annexins II, V, and VI belong to a family of Ca(2+)-dependent phospholipid-binding proteins that have been involved mainly in signal transduction, differentiation, membrane trafficking events, or binding to the extracellular matrix, or that might be effective as Ca(2+)-channels. They are abundant in the mammalian myocardium and might play a role in ventricular remodeling and altered calcium handling during heart failure. To test this hypothesis, we compared the expression and distribution of these annexins in nonfailing (n = 9) and failing human hearts with idiopathic dilated cardiomyopathy (n = 11).

Comparative study of respiration kinetics and protein composition of skinned fibers from various types of rat muscle.

The respiration parameters of mitochondria from rat heart muscle and from fast-twitch and slow-twitch skeletal muscle skinned fibers were comparatively analyzed. Electrophoretic patterns of fiber protein composition were also compared. It was found that fibers with low affinity of mitochondria for ADP (i.

Correlation between degree of rupture of outer mitochondrial membrane and changes of kinetics of regulation of respiration by ADP in permeabilized heart and liver cells.

Kinetics of regulation of respiration by ADP in skinned cardiac fibers and permeabilized isolated hepatocytes was compared before and after mitochondrial swelling due to hypoosmotic treatment in 30-50 mOsM solutions. In both systems the apparent Km for ADP was high before mitochondrial swelling and equal to 297 +/- 35 microM and 275 +/- 35 microM, correspondingly. Hypoosmotic treatment resulted in the rupture of outer mitochondrial membrane and in the loss of exogenous cytochrome c, and both in skinned cardiac fibers and permeabilized hepatocytes the value of apparent Km for ADP was decreased in correlation with the extent of the rupture of the outer mitochondrial membrane.

Caffeine and Ca2+ stimulate mitochondrial oxidative phosphorylation in saponin-skinned human skeletal muscle fibers due to activation of actomyosin ATPase.

The rate of mitochondrial oxidative phosphorylation of saponin-skinned human muscle fibers from m. vastus lateralis in the presence of glutamate, malate and ATP is reported to be sensitive to caffeine and to changes of free calcium ion concentration. An approximately twofold increase in respiration was observed by the addition of 15 mM caffeine, because of the efflux of calcium from sarcoplasmic reticulum.

Phosphocreatine pathway for energy transport: ADP diffusion and cardiomyopathy.

Chemically skinned (by treatment with saponin, 40 micrograms/ml) isolated cardiomyocytes were used to study the intracellular diffusion of ADP and creatine (Cr). Stimulation of respiration was studied in these cardiomyocytes without intact sarcolemma and in isolated heart mitochondrial by addition of ADP and Cr in the presence of 0.2 mM ATP (via mitochondrial creatine kinase reaction: Cr + MgATP = MgADP + PCr).

In vivo regulation of mitochondrial respiration in cardiomyocytes: specific restrictions for intracellular diffusion of ADP.

Relative diffusivities of ADP and creatine in cardiomyocytes were studied. The isolated rat cardiomyocytes were lysed with saponin (40 micrograms/ml) to perforate or completely disrupt sarcolemma that was evidenced by leakage of 80-100% lactate dehydrogenase. In these cardiomyocytes mitochondria were used as 'enzymatic probes' to determine the average local concentration of substrates exerting acceptor control of respiration--ADP or creatine (the latter activates respiration via mitochondrial creatine kinase reaction)--when their concentrations in the surrounding medium were changed.

Regulation of succinate dehydrogenase and tautomerization of oxaloacetate.

Highly purified succinate-ubiquinone reductase catalyzes the oxidation of L- or D-malate with a Km and initial Vmax equal to approximately 10(-3) M and approximately 100 nmol/min/mg of protein, respectively. The malate dehydrogenase activity of succinate dehydrogenase rapidly decreases regardless of the presence of glutamate plus glutamate-oxaloacetate transaminase. The inhibitor trapping system, however, prevents the inactivation of succinate dehydrogenase under the conditions when the rate of tautomeric oxaloacetate enol in equilibrium oxaloacetate ketone interconversion is high.

Isolation and properties of oxaloacetate keto-enol-tautomerases from bovine heart mitochondria.

Two highly purified proteins with quite different properties capable of oxaloacetate keto-enol-tautomerase activity (oxaloacetate keto-enol-isomerase, EC 5.3.2.

Oxidation of malate by the mitochondrial succinate-ubiquinone reductase.

The purified succinate-ubiquinone reductase catalyzes the L- (or D-) malate: acceptor oxidoreductase reaction with Km for malate of about 2.10(-3) M and initial Vmax of 50 and 100 nmol per min per mg of protein for L- and D-stereoisomers, respectively (25 degrees C, pH 7.0).