Localization of Basic Fibroblast Growth Factor in Bovine Adrenal Chromaffin Cells

AbstractAdrenal chromaffin cells (CCs) in rodents express a rapidly inactivating, TTX-sensitive sodium current. The current has generally been attributed to Nav1.7, although a possible role for Nav1.3 has also been suggested. Nav channels in rat CCs rapidly inactivate into two separable pathways, which differ in their time course of recovery from inactivation. One population recovers with time constants similar to traditional fast inactivation and the other about 10-fold slower. Inactivation properties suggest that the two pathways result from a single homogenous population of channels. Here we probe the properties and molecular components of the Nav current present in mouse CCs. We first confirm that functional properties of Nav current in rat and mouse cells are generally similar in terms of activation range, steady-state inactivation, and dual pathway fast inactivation. The results then show that all inward Nav current is absent in CCs from Nav1.3 KO mice. Subsequently, in a mouse with KO of fibroblast growth factor homology factor 14 (FGF14), we find that the slow component of recovery from fast inactivation is completely absent in most CCs, with no change in the time constant of fast recovery. Experiments probing the use-dependence of Nav current diminution between WT and FGF14 KO mice directly demonstrate a role of slow recovery from inactivation in determination of Nav current availability. Overall, the results indicate that the FGF14-mediated inactivation is the major determinant in defining use-dependent changes in Nav availability in CCs. We also consider the potential impact that inactivating FGF’s with different recovery kinetics can exert on differential use-dependent changes in Nav availability.

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Basic fibroblast growth factor in chromaffin cells

Journal of the Autonomic Nervous System ◽

10.1016/0165-1838(91)90217-q ◽

1991 ◽

Vol 33 (2) ◽

pp. 212

Author(s):

R. Westermann ◽

D. Blottner ◽

C. Grothe ◽

K. Unsicker

Keyword(s):

Growth Factor ◽

Fibroblast Growth Factor ◽

Basic Fibroblast Growth Factor ◽

Chromaffin Cells ◽

Fibroblast Growth

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Immunocytochemical localization of basic fibroblast growth factor in bovine adrenal gland, ovary, and pituitary.

Journal of Histochemistry & Cytochemistry ◽

10.1177/37.12.2685112 ◽

1989 ◽

Vol 37 (12) ◽

pp. 1877-1883 ◽

Cited By ~ 41

Author(s):

C Grothe ◽

K Unsicker

Keyword(s):

Growth Factor ◽

Adrenal Gland ◽

Fibroblast Growth Factor ◽

Basic Fibroblast Growth Factor ◽

Stromal Cells ◽

Chromaffin Cells ◽

Endocrine Cells ◽

Zona Glomerulosa ◽

Fibroblast Growth

We studied the distribution of basic fibroblast growth factor (bFGF) immunoreactivity in bovine adrenal gland, ovary, and pituitary, using a polyclonal anti-bFGF antibody. In the adrenal gland, the inner layers of the capsule, the zona glomerulosa of the cortex, and the chromaffin cells of the adrenal medulla were intensely stained. In the ovary, follicular epithelial cells of growing follicles and granulosa cells of mature follicles showed strong bFGF-like immunoreactivity. Endocrine cells of the pituitary anterior and intermediate lobes displayed a positive immunoreaction. Blood vessels, including endothelial and smooth muscle cells, as well as stromal cells in all three organs studied, were not stained. This distribution pattern of bFGF immunoreactivity is only partially compatible with the established mitogenic role of this protein, and suggests a wider spectrum of bFGF functions.

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