Neurotransmitter receptors as signaling platforms in anterior pituitary cells

Abstract

The functions of anterior pituitary cells are controlled by two major groups of hypothalamic and intrapituitary ligands: one exclusively acts on G protein-coupled receptors and the other activates both G protein-coupled receptors and ligand-gated receptor channels. The second group of ligands operates as neurotransmitters in neuronal cells and their receptors are termed as neurotransmitter receptors. Most information about pituitary neurotransmitter receptors was obtained from secretory studies, RT-PCR analyses of mRNA expression and immunohistochemical and biochemical analyses, all of which were performed using a mixed population of pituitary cells. However, recent electrophysiological and imaging experiments have characterized γ-aminobutyric acid-, acetylcholine-, and ATP-activated receptors and channels in single pituitary cell types, expanding this picture and revealing surprising differences in their expression between subtypes of secretory cells and between native and immortalized pituitary cells. The main focus of this review is on the electrophysiological and pharmacological properties of these receptors and their roles in calcium signaling and calcium-controlled hormone secretion.

Long‐term stiripentol administration, an anticonvulsant drug, does not impair sperm parameters in rats

“…The tuberoinfundibular pathway (TI) involves neurons secreting dopamine and GABA, and neurons that store GABA alone (Everitt et al., 1984; Meister & Hökfelt, 1988). GABA released to the portal circulation of the pituitary gland modifies the endocrine function of anterior pituitary cells as GABA and GABA A receptors are present in most of them (Zemková & Stojilkovic, 2018). Among others, it modulates prolactin secretion, and daily fluctuation of GABA concentration in pituitary gland correlates with daily fluctuation of prolactin secretion (Caride et al., 2009; Zemková & Stojilkovic, 2018).…”

“…GABA released to the portal circulation of the pituitary gland modifies the endocrine function of anterior pituitary cells as GABA and GABA A receptors are present in most of them (Zemková & Stojilkovic, 2018). Among others, it modulates prolactin secretion, and daily fluctuation of GABA concentration in pituitary gland correlates with daily fluctuation of prolactin secretion (Caride et al., 2009; Zemková & Stojilkovic, 2018). We did not observe any differences in prolactin (PRL) levels between groups both in Week 4 and Week 24.…”

Electrochemical Nanocomposite Single-Use Sensor for Dopamine Detection

“…Neurotransmission is the process of exchanging and using of this information, and it occurs within a discrete group of highly specialized cells called neurons. Neurotransmitters are substances that aid in transmitting the impulses between the nerve cells, or between a nerve and a muscle, acting as messengers in the synaptic transmission process [1]. They are essential for human health and any imbalance in their activities can cause serious mental disorders.…”

Propofol Requirement in Patients with Growth Hormone-Secreting Pituitary Tumors Undergoing Transsphenoidal Surgery

“…It is well known that the secretion of growth hormones from the pituitary gland is regulated primarily by hormones released from the hypothalamus, i.e., growth hormone-releasing hormone and growth hormone-inhibiting hormone. The hypothalamic pituitary neuroendocrine axis is controlled by complex networks of various hormones, and hypothalamic GABA can stimulate anterior pituitary hormone secretion, including that of growth hormones [7,8,9,10]. Furthermore, the synthesis of GABA within the pituitary gland has been reported, which suggests that pituitary GABA has an autocrine function [11].…”