Elimination of protein-food ingested into the crop, and failure of ovarian development in female mosquitoes, Culex pipiens pollens.

ABSTRACT. Sugar-free egg albumin solution was 'force fed' to female C.pipiens pallens Coquillett, by first stimulating their labella briefly with 1.0 M sucrose, so that they then took the protein meal into the crop. This protein-food was nevertheless easily eliminated by the females, totally undigested, so that it failed to activate oogenesis, just as sugared albumin fails to do so also.     

Norepinephrine Induces Apoptosis in Skin Melanophores by Attenuating cAMP‐PKA Signals Via α2‐Adrenoceptors in the Medaka,Oryzias Latipes

The density of skin melanophores in many teleost fish decreases during long‐term adaptation to a white background. Using the medaka, Oryzias latipes, we previously reported that apoptosis is responsible for the decrease in melanophores, and that a sympathetic neurotransmitter, norepinephrine (NE), induces their apoptosis in skin tissue cultures. In this study, we show that NE‐induced apoptosis of melanophores is mediated by the activation of α2‐adrenoceptors. Clonidine, an α2‐adrenoceptor agonist, induced apoptotic melanophore death in skin organ culture, while phenylephrine, an α1‐adrenoceptor agonist, had no effect. NE‐induced apoptosis was diminished by an α2‐adrenoceptor antagonist, yohimbine, but an α1‐adrenoceptor antagonist, prazosin, did not abrogate the effect of NE. Furthermore, forskolin inhibited NE‐induced apoptosis, while an inhibitor of PKA, H‐89, mimicked the effect of NE. These results suggest that NE induces apoptosis in melanophores by attenuating cAMP‐PKA signaling via α2‐adrenoceptors.