Differential and coordinate regulation of TH and PNMT mRNAs in chromaffin cell cultures by second messenger system activation and steroid treatment

In this study, we have examined the expression and intracellular localisation of the myelin protein 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNP) in bovine adrenal medullary chromaffin cell cultures. By immunoblotting, using two distinct anti-CNP monoclonal antibodies, CNP was detected in medullary cell cultures and expression of CNP was confirmed by reverse transcription and PCR amplification. CNP did not leak from digitonin-permeabilised chromaffin cells, suggesting that there is no cytosolic pool of this protein. Immunofluorescence studies with both antibodies showed that all cells in the medullary chromaffin cell culture were stained with a punctate appearance consistent with an intracellular localisation for CNP. More specifically it was demonstrated that CNP is co-localised with mitochondria. Various cell types in chromaffin cell cultures were stained with a mitochondrial pattern and CNP staining was co-localised with mitochondrial staining. These results show that CNP is a widely expressed protein that is associated with mitochondria and provides new clues as to its cellular function outside of myelin structures.

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Calmodulin and Its Role in the Second-Messenger System

Current Topics in Cellular Regulation ◽

10.1016/b978-0-12-152815-7.50006-5 ◽

1979 ◽

pp. 47-107 ◽

Cited By ~ 173

Author(s):

JERRY H. WANG ◽

DAVID MORTON WAISMAN

Keyword(s):

Second Messenger ◽

Messenger System

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Inhibition of Jv by ANF in rat proximal straight tubules requires angiotensin

AJP Renal Physiology ◽

10.1152/ajprenal.1989.257.5.f907 ◽

1989 ◽

Vol 257 (5) ◽

pp. F907-F911 ◽

Cited By ~ 5

Author(s):

J. L. Garvin

Keyword(s):

Angiotensin Ii ◽

Atrial Natriuretic Factor ◽

Second Messenger ◽

Fluid Absorption ◽

Straight Tubule ◽

Cyclic Monophosphate ◽

Natriuretic Factor ◽

Straight Tubules ◽

Proximal Straight Tubule ◽

Messenger System

The effects of atrial natriuretic factor (ANF) on fluid absorption (Jv) by isolated perfused proximal straight tubules of rats were investigated. ANF alone (10(-8) M) added to the bath had no significant effect on absorption. In contrast, when tubules were first treated with 1.6 X 10(-10) M angiotensin II, this same concentration of ANF lowered fluid absorption from 0.99 +/- 0.03 to 0.69 +/- 0.02 nl.mm-1.min-1. A lower dose of ANF, 2 X 10(-10) M, reduced fluid absorption in the presence of angiotensin II from 1.13 +/- 0.06 to 0.65 +/- 0.05 nl.mm-1.min-1, an inhibition of 40%. Since guanosine 3',5'-cyclic monophosphate (cGMP) is reportedly part of the second messenger system of ANF, the effects of dibutyryl-cGMP (DBcGMP) on fluid absorption were studied. This membrane-permeant form of cGMP mimicked the effects of ANF, reducing fluid absorption from 1.15 +/- 0.18 to 0.54 +/- 0.08 nl.mm-1.min-1. These studies suggested the following: 1) ANF can regulate fluid absorption in the proximal nephron; 2) this inhibition occurs only in the presence of angiotensin; and 3) cGMP is part of the second messenger system of ANF in the rat proximal straight tubule, as it is in other tissues.

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