Stimulation of d2 dopamine receptors decreases intracellular calcium levels in rat anterior pituitary cells but not striatal synaptosomes: A flow cytometric study using indo-1

Synapse ◽  
1989 ◽  
Vol 4 (4) ◽  
pp. 353-370 ◽  
Author(s):  
Marina E. Wolf ◽  
Gregory Kapatos
Keyword(s):  
Intracellular Calcium ◽  
Dopamine Receptors ◽  
Anterior Pituitary ◽  
Pituitary Cells ◽  
D2 Dopamine Receptors ◽  
Flow Cytometric ◽  
Anterior Pituitary Cells ◽  
Flow Cytometric Study ◽  
Stimulation Of

Control of secretion in anterior pituitary cells--linking ion channels, messengers and exocytosis

1988 ◽  
Vol 139 (1) ◽  
pp. 287-316
Author(s):  
W. T. Mason ◽  
S. R. Rawlings ◽  
P. Cobbett ◽  
S. K. Sikdar ◽  
R. Zorec ◽  
...  
Keyword(s):  
Ion Channels ◽  
Intracellular Calcium ◽  
Anterior Pituitary ◽  
Hormone Secretion ◽  
Cell Types ◽  
Pituitary Cell ◽  
Pituitary Cells ◽  
Calcium Activity ◽  
Anterior Pituitary Cells ◽  
Voltage Dependent

Normal anterior pituitary cells, in their diversity and heterogeneity, provide a rich source of models for secretory function. However, until recently they have largely been neglected in favour of neoplastic, clonal tumour cell lines of pituitary origin, which have enabled a number of studies on supposedly homogeneous cell types. Because many of these lines appear to lack key peptide and neurotransmitter receptors, as well as being degranulated with accompanying abnormal levels of secretion, we have developed a range of normal primary anterior pituitary cell cultures using dispersion and enrichment techniques. By studying lactotrophs, somatotrophs and gonadotrophs we have revealed a number of possible transduction mechanisms by which receptors for hypothalamic peptides and neurotransmitters may control secretion. In particular, the transduction events controlling secretion from pituitary cells may differ fundamentally from those found in other cell types. Patch-clamp recordings in these various pituitary cell preparations have revealed substantial populations of voltage-dependent Na+, Ca2+ and K+ channels which may support action potentials in these cells. Although activation of these channels may gate Ca2+ entry to the cells under some conditions, our evidence taken with that of other laboratories suggests that peptide-receptor interactions leading to hormone secretion occur independently of significant membrane depolarization. Rather, secretion of hormone and rises in intracellular calcium measured with new probes for intracellular calcium activity, can occur in response to hypothalamic peptide activation in the absence of substantial changes in membrane potential. These changes in intracellular calcium activity almost certainly depend on both intracellular and extracellular calcium sources. In addition, strong evidence of a role for multiple intracellular receptors and modulators in the secretory event suggests we should consider the plasma membrane channels important for regulation of hormone secretion to be predominantly agonist-activated, rather than of the more conventional voltage-dependent type. Likewise, evidence from new methods for recording single ion channels suggests the existence of intracellular sites for channel modulation, implying they too may play an important role in secretory regulation. We shall consider new data and new technology which we hope will provide key answers to the many intriguing questions surrounding the control of pituitary hormone secretion. We shall highlight our work with recordings of single ion channels activated by peptides, and recent experiments using imaging of intracellular ionized free calcium.(ABSTRACT TRUNCATED AT 250 WORDS)

Beta-Adrenergic Stimulation of Growth Hormone Release from Perifused Rat Anterior Pituitary Cells

1983 ◽  
Vol 37 (6) ◽  
pp. 473-475 ◽  
Author(s):  
Susan N. Perkins ◽  
William S. Evans ◽  
Michael O. Thorner ◽  
Michael.J. Cronin
Keyword(s):  
Growth Hormone ◽  
Anterior Pituitary ◽  
Pituitary Cells ◽  
Hormone Release ◽  
Growth Hormone Release ◽  
Adrenergic Stimulation ◽  
Beta Adrenergic ◽  
Anterior Pituitary Cells ◽  
Stimulation Of
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