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The activation of the Na+–H+exchanger 1 (NHE1) and extracellular-signal regulated kinase (ERK) phospho rylation in Chinese hamster lung fibroblasts (CCL39) was characterized in response to the specific α1-adrenergic agonist, phenylephrine (PE). Addition of 100 µmol PE/L increased the steady-state intracellular pH (pHi) by 0.16 ± 0.03 pH units, as well as increasing the phosphorylation of ERK. The response of NHE1 to PE in CCL39 cells was determined by the use of specific antagonists. Use of 2 specific chemical inhibitors of phosphoinositide-specific phospholipase C (PLC) reduced the ability of PE to activate either the exchanger or ERK. Studies were conducted in PLCβ-deficient cell lines derived from parental CCL39 cells. NHE1 activity in both mutant cell lines was increased in response to phorbal esters or lysophosphatidic acid, whereas the addition of PE only caused a minimal change in either pHior ERK phosphorylation. These results, combined with reconstitution experiments with exogenously expressed PLCβ1, PLCβ2, or PLCβ3, revealed that stimulation of NHE1 activity by PE in CCL39 cells is a PLCβ1-coupled event. Furthermore, the data indicate that α1-adrenergic signaling of PLCβ is upstream of ERK activation. These data demonstrate that PLCβ1is primarily involved in the activation of NHE1 in CCL39 fibroblasts.Key words: CCL39, sodium hydrogen exchanger, ERK, α1-adrenergic receptor, phospholipase Cβ.

The reporting period has shown that Space has become a firmly established domain in observational Astrophysics, also in the low energy astrophysics area. The launching of new spacecraft is always an important addition to the capabilities of the Astronomers, but the availability of space observatories is strongly affected by the fact that they disappear as their subsystems become damaged or, for other reasons, become inoperable. The relatively short life of astronomical space facilities has generated new dynamic in the life cycle of observational tools for the astronomer, rather different from that for ground facilities. Launch failures or the final in-orbit functionality verification can also very strongly affect the availability of observational capabilities in space astrophysics. The only spacecraft designed without this built-in life time restriction, is the Hubble Space Telescope, which can be serviced by the Space Shuttle.

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An infrared camera for astronomical research has been developed at the Naval Research Laboratory, Center for Advanced Space Sensing. A series of observations in December 1990 at the 2.3-meter Wyoming Infrared Observatory (WIRO) yielded new astronomical images of the star forming regions M42/IRc 1, NGC 2264/IRS1 and NGC 7538/IRS1 at 12 and 20 microns, in addition to images of a variety of stellar calibrators. Based on a 10x50 element, Si:As BIBIB/SWIFET hybrid array fabricated at Rockwell International, this camera system (IRCAM) achieves its peak sensitivity between 18-22 microns, making it well matched for observing in the 20 micron atmospheric window. Substantial sensitivity is also available at 10 microns so that near simultaneous observations are feasible through both windows. IRCAM employs four, (Delta lambda -> 1.0 microns) filters at 8, 10, 12 and 12.4 microns; a broad band filter: 18-24 microns, as well as standard K, L, and M filters. The array field of view is 20" x 100" with 1.6" pixels surrounded by 0.4" dead space, allowing diffraction limited observing at 20 microns with a 2.3-meter telescope. In this paper, we describe the camera system, and present the results of the astronomical observations conducted at the Wyoming Infrared Observatory.