Organotypic cultures of the rat anterior pituitary: morphology, physiology and cell-to-cell communication

Gap junction signalling is a stress-regulated component of adrenal neuroendocrine stimulus-secretion coupling in vivo

“…Although ketamine does not modify basal catecholamine secretion 45 , a direct measurement of plasma catecholamines, in a freely moving mouse submitted or not to various stress paradigms, will be necessary to definitely answer this question. Although a direct cell-cell communication through gap junctions has been described in many endocrine/neuroendocrine tissues [46][47][48][49] , including the adrenal medulla 6,7,11 , its contribution to hormone secretion in vivo has been unambiguously established so far only for insulin 50,51 and renin 49,52 . Very recent studies performed in the anterior pituitary 53,54 strongly support a crucial role for gap junctions in endocrine tissue output, suggesting that the plasticity of gap junction-coupled endocrine cell network is a key element underlying functional adaptation of hormone release at the population level.…”

Synchronized Spontaneous Ca2+ Transients in Acute Anterior Pituitary Slices

“…To increase the rate of Neurobiotin dialysis, depolarizing pulses (500-ms duration, 0.5 Hz) were periodically applied. In some cells, the presence of gap junctional communication was assessed by using the size exclusion properties of dextran conjugates (9). Cells were dialyzed with a patch pipette containing 1% Neurobiotin plus 2 mg/ml dextran Texas Red (lysine fixable, M r 3,000) for at least 10 min.…”

“…Although electrical activity has already been detected in the anterior pituitary gland, both in vivo and in tissue preparations (7)(8)(9), the dynamics and organization of [Ca 2ϩ ] i rises associated with spontaneous action potentials have not yet been investigated at the tissue level. Based on the heterogeneous distribution of the five secretory cell types throughout the tissue (10), endocrine cells would display asynchronous firing so that the overall activity of each secretory type would simply reflect the average of single cell events.…”

“…First, both endocrine and non-endocrine (folliculostellate) pituitary cells release various products (ATP, dopamine, and so forth), which locally act on neighboring cells (19 -21). Second, gap junctions present in the anterior pituitary (9,(22)(23)(24) may allow both metabolic and electrical coupling between connected cells.…”

In vitroInduction of Luteinizing Hormone Synthesis by Estrogen in Organ-Cultured Pituitary Glands of the Japanese Eel, Anguilla japonica

“…In mammals, organ culture of the pituitary gland is known as a valuable technique for the study of GTH production (Martin and Klein, 1976;Baker and Young, 1979;Guérineau et al ., 1997). This seems also to be the case in some teleosts such as the rainbow trout (Fåhraeus-van Ree et al ., 1983) and goldfish (Huggard et al ., 1996).…”