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Since Darwin published the "Origin," great progress has been made in our understanding of speciation mechanisms. The early investigations by Mayr and Dobzhansky linked Darwin's view of speciation by adaptive divergence to the evolution of reproductive isolation, and thus provided a framework for studying the origin of species. However, major controversies(More)
Understanding the evolution of reproductive isolation is tantamount to describing the origin of species. Therefore, a primary goal in evolutionary biology is to identify which reproductive barriers are most important to the process. To achieve this goal, the strength of multiple forms of isolation must be compared in an equivalent manner. However, a(More)
The current study was conducted to investigate hormonal regulation of cytochrome P450 2C11 (CYP2C11) in rat liver and kidney of adult male rats. In two experiments, hypophysectomy (Hx) resulted in decreased (P < .05) hepatic CYP2C11 apoprotein and mRNA levels. Growth hormone (GH) replacement of Hx rats prevented the decline in hepatic CYP2C11 apoprotein and(More)
1. In the cell-attached and inside-out patch-clamp experiments using undispersed endothelial cells of the rat intrapulmonary artery, the majority of channels were cation selective. 2. Under physiological ionic conditions, the I-V relationship for the inward currents fell to -80 mV and the slope conductance was 22.5 pS. There was an inward rectification and(More)
In ring preparations of the rabbit mesenteric artery, the Ca-contraction, but not the noradrenaline (NA)-contraction, was inhibited by FRC-8653 (10(-9)-10(-5) M) in a concentration-dependent manner, although with a potency 50-100 times weaker than that of nicardipine. The actions of FRC-8653 on Ca-contraction appeared more slowly (over 1 hr) than those of(More)
In isolated buccal segment of the rabbit facial vein, electrical responses produced by perivascular nerve stimulation and exogenously applied noradrenaline (NA) were recorded from the smooth muscle cells using microelectrode. Perivascular nerve stimulation hyperpolarized the smooth muscle cell membrane. The hyperpolarization was converted to depolarization(More)
Examining reproductive isolating barriers is essential for understanding processes of speciation. Sexual isolation has been shown to contribute to speciation in many sympatric taxa; however, its role in parapatric taxa with reduced interspecific gene flow is poorly understood. I investigated the extent of sexual isolation in two closely related Neotropical(More)
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