Maternal experience prevents pup-killing in mice induced by peripheral anosmia

The ability of experience to modify pup-killing by a peripheral anosmia was investigated in a 2 × 2 design in which experience and anosmia were manipulated. Anosmia induced by zinc sulfate flush of the nasal epithelium resulted in pup-killing in 13 of 15 primiparous litters, whereas only 2 of 15 multiparous mothers were pup-killers. These results suggest that primiparous mothers depend heavily on olfaction and that a dichotomy exists between the peripheral chemical induced anosmia (modifiable by experience) and the central, whole bulb aspiration induced anosmia, not modifiable by experience.     

Megakaryocyte interaction with subendothelial extracellular matrix is associated with adhesion, platelet-like shape change, and thromboxane A2 production

We have examined the morphological and secretory behavior of rat and guinea pig megakaryocytes exposed for up to 24 hours to extracellular matrix produced by cultured bovine endothelial cells. By phase-contrast microscopy of living cells and in more detail by scanning electron microscopy, the megakaryocytes showed a nonreversible adherence, an extensive formation of filopodia around the periphery like the rays of the sun, and a tendency toward flattening. These filopodia were generally linear with attenuated tips and were larger than, but resembled the filopodia of, rat or guinea pig platelets exposed to this extracellular matrix. In contrast, isolated megakaryocytes on glass or on uncoated plastic surfaces did not show these responses; adherence, in the face of gentle agitation before fixation, was minimal, with rare filopodia and no flattening. Megakaryocytes that interacted with the extracellular matrix produced significant amounts of thromboxane A2, but this did not occur on uncoated surfaces and could not be attributed to other contaminating cells in the megakaryocyte suspensions. The appearance in megakaryocytes of these typical platelet responses indicates that megakaryocytes acquire the functional capabilities of platelets by the synthesis and assembly of platelet substances and organelles. Thromboxane production by megakaryocytes stimulated by the extracellular matrix is a readily quantifiable measure of this capacity.