GABA acts directly on cells of pituitary pars intermedia to alter hormone output

@article{Tomiko1983GABAAD,
  title={GABA acts directly on cells of pituitary pars intermedia to alter hormone output},
  author={Sally A. Tomiko and P. Stephen Taraskevich and William W. Douglas},
  journal={Nature},
  year={1983},
  volume={301},
  pages={706-707}
}
Recent immunohistochemical evidence from the rat, indicating that γ-aminobutyric acid (GABA)-containing fibres of central nervous origin project to the pars intermedia of the pituitary1,2, prompts inquiry into the function of this innervation. There is electrophysiological evidence that GABA acts directly on melanotrophs isolated from rat, through bicuculline-blockable receptors, to increase Cl− conductance and thereby drive the membrane potential towards the Cl− equilibrium potential in these… 

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The results indicate that GABA is a physiologically important factor for regulation of the pars intermedia in Xenopus laevis.

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This work has used ion-sensitive microelectrodes to detect the presence of GABA-A and GABA-B receptors in the neurointermediate lobe (NIL) of the rat pituitary and revealed the specific effects of isoguvacine and baclofen on excitation-secretion coupling in the NIL.

Allosteric Modulation of the GABA‐Induced Chloride Current in Frog Melanotrophs a

The intermediate lobe of the pituitary is innervated by fibers containing a-aminobutyric acid (GABA) which modulates the secretory activity of melanotroph cells through activation of GABAA

Electrophysiology of neurosecretory cells from the pituitary intermediate lobe.

TLDR
The characteristics of voltage-dependent conductances, the contribution of these conductances to action potentials and their role in stimulus-secretion coupling in cells of the pituitary pars intermedia are examined.
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References

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GABA directly affects electrophysiological properties of pituitary pars intermedia cells

TLDR
The brain can influence the endocrine cells of the pars intermedia directly through GABAergic mechanisms, and the ionic and pharmacological characteristics of this action of GABA resemble those encountered at many GABAergic synapses in the central nervous system (CNS).

Release of α-Melanocyte-Stimulating Hormone from Dispersed Cells of the Intermediate Lobe of the Rat Pituitary Gland: Involvement of Catecholamines and Adenosine 3′,5′-Monophosphate

Treatment of the neurointermediate lobe of the rat pituitary gland with mechanical agitation in the presence of trypsin and DNAse results in a preparation of cells which secrete αMSH and synthesize

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Activity of glutamic acid decarboxylase GluDCase, the biosynthetic enzyme of gamma-aminobutyric acid (GABA) was measured in low-speed homogenate supernatant of the neural and intermediate

Calcium component to action potentials in rat pars intermedia cells.

TLDR
The demonstration of a Ca component to the predominantly Na‐dependentaction potentials of pars intermedia cells heightens the possibility that these action potentials participate in the regulation of secretion.

GABA neuron systems in hypothalamus and the pituitary gland. Immunohistochemical demonstration using antibodies against glutamate decarboxylase.

TLDR
The distribution of gamma-aminobutyric acid nerve fibers and cell bodies in the rat hypothalamus and pituitary gland was immunohistochemically examined and provided a morphological basis by which GABA of hypothalamic origin may regulate the neuroendocrine system.

HORMONE SECRETION BY CELLS DISSOCIATED FROM RAT ANTERIOR PITUITARIES

TLDR
The results demonstrate that function and morphologic integrity are preserved in this cell system, suitable for the study of various aspects of pituitary secretion and its control.

Coordinated action of calcium ion and adenosine 3',5'-monophosphate upon the release of alpha-melanocyte-stimulating hormone from the intermediate lobe of the rat pituitary gland.

TLDR
The results indicate that Ca++ is essential for the release of alpha MSH, and that cAMP in some way enhances the effects of Ca++ upon the release process.

Action potentials in gland cells of rat pituitary pars intermedia: inhibition by dopamine, an inhibitor of MSH secretion

TLDR
Cells were dissociated from rat pituitary pars intermedia, maintained in culture, and subjected to electrophysiological study to establish an experimental procedure for cell reprograming.