Cytochemical analysis of intracellular calcium distribution in the anterior pituitary of the rat

1981 ◽  
Vol 220 (1) ◽  
Author(s):  
M.Patricia Leuschen ◽  
C.Michael Moriarty ◽  
H.Wayne Sampson ◽  
I. Piscopo
Keyword(s):  
Intracellular Calcium ◽  
Anterior Pituitary ◽  
Calcium Distribution ◽  
Cytochemical Analysis

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)

Intracellular calcium distribution in apoptosis of HL-60 cells induced by harringtonine: intranuclear accumulation and regionalization

1998 ◽  
Vol 127 (1-2) ◽  
pp. 113-121 ◽  
Author(s):  
Min Fang ◽  
Hongqing Zhang ◽  
Shaobai Xue ◽  
Nan Li ◽  
Liming Wang
Keyword(s):  
Intracellular Calcium ◽  
Calcium Distribution

Ionotropic glutamate receptor activation increases intracellular calcium in prolactin-releasing cells of the adenohypophysis

2006 ◽  
Vol 291 (6) ◽  
pp. E1188-E1196 ◽  
Author(s):  
Frederick P. Bellinger ◽  
Bradley K. Fox ◽  
Wing Yan Chan ◽  
Lori K. Davis ◽  
Marilou A. Andres ◽  
...  
Keyword(s):  
Intracellular Calcium ◽  
Anterior Pituitary ◽  
Receptor Activation ◽  
Nmda Receptor Antagonist ◽  
Pituitary Cells ◽  
The Central Nervous System ◽  
To Receive ◽  
Dose Dependent Increase ◽  
Dose Dependent ◽  
The Brain

Endocrine cells of the anterior pituitary are controlled by the central nervous system through hormonal interactions and are not believed to receive direct synaptic connections from the brain. Studies suggest that some pituitary cells may be modulated by the neurotransmitter glutamate ( 5 , 16 ). We investigated prolactin (PRL)-releasing cells of the anterior pituitary of a euryhaline fish, the tilapia ( Oreochromis mossambicus), for the presence of possible glutamate receptors (GluRs). Fura-2 imaging addressed the ability of glutamate to increase intracellular calcium. We observed a dose-dependent increase in intracellular calcium with transient perfusion (1–2 min) of glutamate (10 nM to 1 mM) in two-thirds of imaged cells. This increase was attenuated by the ionotropic GluR antagonist kynurenic acid (0.5–1.0 mM). The increase was also blocked or attenuated by antagonists of L-type voltage-gated calcium channels. The GluR agonist α-amino-3-hydroxy-5-methylisoxazole propionic acid (AMPA; 100 μM) produced intracellular calcium increases that were reversibly blocked by the selective AMPA antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). In contrast, the selective agonist N-methyl-d-aspartate (NMDA; 100 μM to 1 mM in magnesium-free solution with 10 μM glycine) had no effect on intracellular calcium. Radioimmunoassays demonstrated that glutamate stimulated PRL release. CNQX but not the NMDA receptor antagonist 2-amino-5-phosphonovaleric acid blocked this release. Antibodies for mammalian AMPA- and NMDA-type GluR produced a similar punctate immunoreactivity in the periphery of PRL cells. However, the NMDA antibody recognized a protein of a different molecular mass in PRL cells compared with brain cells. These results clearly indicate the presence of GluRs on tilapia PRL cells that can stimulate PRL release.

Effect of halomethanes on intracellular calcium distribution in hepatocytes

Life Sciences ◽  
1984 ◽  
Vol 35 (11) ◽  
pp. 1231-1240 ◽  
Author(s):  
William J. Brattin ◽  
Robert L. Waller
Keyword(s):  
Intracellular Calcium ◽  
Calcium Distribution

Intracellular calcium distribution map and chemical shift of neurons examined by computer controlled electron probe X-ray microanalyser

1978 ◽  
Vol 36 (2) ◽  
pp. 126-127
Author(s):  
Minoru Onozuka ◽  
Eiichi Sugaya ◽  
Aiko Sugaya ◽  
Masayoshi Usami
Keyword(s):  
Chemical Shift ◽  
Intracellular Calcium ◽  
Electron Probe ◽  
Cellular Function ◽  
Distribution Map ◽  
X Ray ◽  
Calcium Distribution ◽  
Computer Controlled ◽  
Bursting Activity

The role of divalent cations, particularly of calcium, has gained increasing interest as a charge carrier and in processes such as regulation of enzymatic activities, in secretions of humoral transmitters and initiation of muscle contraction. The role of calcium has become very important in manifesting the bursting activity of neurons by various electrophysiological techniques, especially by voltage clamping. The distribution of calcium compared with the ultrastructure of nerve cells, however, has not been widely investigated. Analysis by the electron probe X-ray microanalyser(EPXMA) makes this type of research easier. To determine the relationship between calcium localization within the neuron and cellular function, we tried to make an intracellular calcium distribution map of the normal state and that during bursting activity by the computer controlled EPXMA. We also detected the chemical shift between the different states of cellular function caused by the intracellular calcium binding state.

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