Off-cells

When a temperate phage is mixed with sensitive indicator bacteria and plated as described above, the reaction at each focus of infection is generally a combination of lytic and lysogenic responses. Some bacteria will be lysed and produce phage, others will survive as lysogenic cells, and the plaque becomes visible as a partial area of clearing in the bacterial lawn. It is possible to pick off cells from the central areas of these plaques and demonstrate that they carry prophage. 

Figure 14.2 Hypocretinergic activity dependent on the states of vigilance. During wakefulness, metabolic, circadian, and behavioral inputs converge on hypocretin neurons, which activate noradrenergic neurons in the locus coeruleus and promote arousal. During non-REM sleep, the activity of hypocretin neurons decreases, but the inhibitory influence of REM-off neurons on REM-on cells is still effective. During REM sleep, hypocretin and REM-off cells are silent, disinhibiting REM-on cells. Reprinted with permission from Sutcliffe de Lecea (2002). (See also Plate 7.)...

Hicke, L. Gettin down with ubiquitin turning off cell-surface receptors, transporters and channels. Trends Cell Biol. 9 107-12.1999. 

Hicke L (1999) Gettin down with ubiquitin turning off cell-surface receptors, transporters and channels. Trends Cell Biol 9 107-12 Hicke L, Riezman H (1996) Ubiquitination of a yeast plasma membrane receptor signals its ligand-stimulated endocytosis. Cell 84 277-287 Hicke L, Zanolari B, Riezman H (1998) Cytoplasmic tail phosphorylation of the a-factor receptor is required for its ubiquitination and internalization. J Cell Biol 141 349-358... 

Apotosis has an indispensable role in development and differentiation processes (review Vaux and Korsmeyer, 1999), especially in the embryo. Here, it provides a means to switch off cells no longer needed during embryonal morphogenesis and syn-aptogenesis. 

Reciprocal Interaction Between Cholinergic REM-On and Aminergic REM-Off Cells... 

To us, it happened twice once when we unwittingly probed the locus coeruleus looking for REM-on cells and found, by mistake, our first REM-off cells and later, when we were looking for more REM-off cells in the peribrachial region of the lateral pons, and discovered instead the most impressive REM-on cells we had ever seen, the PGO burst cells. 

The first observation was the more unexpected because we were under the mistaken impression that the locus coeruleus should turn on, not off, in REM. But once we realized that we had the role of norepinephrine backwards, it was not difficult to find other REM-off cells—not only in the locus coeruleus, but also in the raphe nuclei—and to see that both of the pontine aminergic neuromodulators supported waking just as any extension of Hess s principles would suggest. Even the central sympathetic system works toward ergotrophic ends. Eor sleep to occur, this system must first be deactivated to allow NREM sleep to develop, and then actively suppressed, to allow REM to develop. 

Pour off cell suspension into a sterile plastic universal container. 

According to the mechanisms of release, organic rhizodepositions may be grouped into these major fractions lysates, leachates from sloughed-off cells, and dead tissues as a consequence of root turnover. In contrast, root exudates (2-10% of translocated carbon) are released from intact root cells either passively as diffusates or actively as excretions or secretions with specific functions (Grayston et al., 1996 Neumann... 

Check for cell detachment by holding unit up to the light. Return unit to hood, remove cap, and pour off cell suspension into the collection flask containing FBS. 

The antinociceptive effects of mu opioid agonists within the RVM require activation of a class of neurons termed off-cells that exert a net inhibitory effect on nociception [4-6], Mu opioid activation of off-cells is indirect, and triggered by disinhibition. In addition to the indirect activation of off-cells, mu opioids inhibit another class of neurons in RVM, termed on-cells. This inhibition is direct, but suppression of on-cell discharge is not sufficient to produce behavioral analgesia. Opioid inhibition of on-cells may however assume an important role in inflammatory pain states, in which these neurons likely contribute to hyperalgesia [7]. 

Therefore, another possibility in animal studies is to wash out the upper jejunum with a small volume of bicarbonate buffer, and use this fluid as a medium to determine the stability of a test macromolecule or formulation. A similar approach can be used to study enzyme activities in the colon in animals. It should be noted that the preparations should not be centrifuged, but used in their entirety as enzymes can bind to particulate matter or are on the surfaces of bacteria in the case of colon contents (Woodley 1991). Fluid thus obtained from the upper intestine should contain all the pancreatic enzymes, bile salts and sloughed-off cells, but again getting the concentrations right is not obvious. 

It has been shown that excitatory ai-adrenoceptor is present on both On and Off cells, but the inhibitory a2-adrenoceptor is present only on the Off cells, and the activation of On cells can be involved in the increased pain sensitivity during opioid withdrawal (Bie et al., 2003). Thus, activation of a2-adrenoceptors in NRM may induce antinociceptive effects (Haws et al., 1990 Proudfit, 1988). The activation of LC neurons by a2-adrenoceptor agonists also produces antinociception, and a2-adrenoceptor activation might contribute to the antinociceptive effects of amygdala... 

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