Role of neurogenic inflammation in the pathogenesis of alopecia areata

Alopecia areata refers to an autoimmune illness indicated by persistent inflammation. The key requirement for alopecia areata occurrence is the disruption of immune-privileged regions within the hair follicles. Recent research has indicated that neuropeptides play a role in the damage to hair follicles by triggering neurogenic inflammation, stimulating mast cells ambient the follicles, and promoting apoptotic processes in keratinocytes. However, the exact pathogenesis of alopecia areata requires further investigation. Recently, there has been an increasing focus on understanding the mechanisms of immune diseases resulting from the interplay between the nervous and the immune system. Neurogenic inflammation due to neuroimmune disorders of the skin system may disrupt the inflammatory microenvironment of the hair follicle, which plays a crucial part in the progression of alopecia areata.

Neuroendocrine System Regulatory Mechanisms: Acute Coronary Syndrome and Stress Hyperglycaemia

Neurohormonal systems are activated in the early phase of acute coronary syndromes to preserve circulatory homeostasis, but prolonged action of these stress hormones might be deleterious. Cortisol reaches its peak at 8 hours after the onset of symptoms, and individuals who have continued elevated levels present a worse prognosis. Catecholamines reach 100-1,000-fold their normal plasma concentration within 30 minutes of ischaemia, therefore inducing the propagation of myocardial damage. Stress hyperglycaemia induces inflammation and endothelial dysfunction, and also has procoagulant and prothrombotic effects. Patients with hyperglycaemia and no diabetes elevated in-hospital and 12-month mortality rates. Hyperglycaemia in patients without diabetes has been shown to be an appropriate independent mortality prognostic factor in this type of patient.

Gonadotrophin-releasing hormone nerve terminals, tanycytes and neurohaemal junction remodelling in the adult median eminence: functional consequences for reproduction and dynamic role of vascular endothelial cells

Although coordinated actions of several areas within the hypothalamus are involved in the secretion of gonadotrophin-releasing hormone (GnRH), the median eminence of the hypothalamus, where the nerve terminals are located, plays a particularly critical role in the release of GnRH. In adult females, prior to the preovulatory surge of GnRH, the retraction of specialised ependymoglial cells lining the floor of the third ventricle named tanycytes allows for the juxtaposition of GnRH nerve terminals with the adjacent pericapillary space of the pituitary portal vasculature, thus forming direct neurohaemal junctions. These morphological changes occur within a few hours and are reversible. Such remodelling may promote physiological conditions to enhance the central release of GnRH and potentiate oestrogen-activated GnRH release. This plasticity involves dynamic cell interactions that bring into play tanycytes, astrocytes, vascular endothelial cells and GnRH neurones themselves. The underlying signalling pathways responsible for these structural changes are comprised of highly diffusible gaseous molecules, such as endothelial nitric oxide, and paracrine communication processes involving receptors of the erbB tyrosine kinase family, transforming growth factor beta 1 and eicosanoids, such as prostaglandin E(2). Some of these molecules, as a result of their ability to diffuse within the median eminence, may also serve as synchronizing cues allowing for the occurrence of functionally meaningful episodes of GnRH secretion by coordinating GnRH release from the GnRH neuroendocrine terminals.

M3 subtype of muscarinic receptors mediate Ca2+ release from intracellular stores in rat prostate neuroendocrine cells

Our previous studies document the expression of adrenoceptors and purinoceptors in the rat prostate neuroendocrine cells (RPNECs). However, a direct investigation of the receptors for acetylcholine (ACh) is still lacking in the prostate neuroendocrine cells. RPNECs were freshly isolated from the ventral lobes of rat prostate by using collagenase. Effects of ACh and various muscarinic antagonists on the intracellular Ca(2+) concentration ([Ca(2+)](c)) were investigated by using the fura-2 spectrofluorimetry. Single-cell RT-PCR analysis was applied to identify the transcripts for the muscarinic receptor subtypes. ACh (5 microM) induced a sharp transient increase in the [Ca(2+)](c) of RPNECs, which was independent of the extracellular Ca(2+). In the same RPNECs, high KCl (60 mM), phenylephrine (5 microM), UTP (P2Y(1/2) agonist, 50 microM), and alpha, beta-meATP (P2X(1/3) agonist, 0.5 microM) also increased the [Ca(2+)](c). The ACh-induced [Ca(2+)](c) change (delta [Ca(2+)](c)) was blocked by atropine or by para-fluorohexahydrosiladifenidol (M(3) antagonist, 0.3 microM), but not by telenzepine (M(1) antagonist, 1 microM) and himbacine (M(2) and M(4) antagonist, 1 microM). The single-cell RT-PCR demonstrated the selective expression of mRNAs for M(3) in RPNECs. In summary, RPNECs express M(3) muscarinic receptors that are linked to the release of Ca(2+) from intracellular stores. The Ca(2+) signals of RPNECs might mediate the parasympathetic regulation of prostate gland.