Oxytocin is a neuropeptide hormone synthesized in magnocellular neurosecretory cells of the paraventricular and supraoptic nuclei in the hypothalamus [1][2]. It is packaged into neurosecretory vesicles and transported down axons to the posterior pituitary gland, where it is released into the bloodstream [1]. Oxytocin is also released within the brain from dendrites and soma of…
Regulation
Neural regulation of LHRH
Luteinizing hormone-releasing hormone (LHRH) is a neurohormone produced in the hypothalamus which regulates reproduction [1]. LHRH neurons project to the median eminence and release LHRH in a pulsatile manner into the hypophyseal portal system [2]. This stimulates the anterior pituitary to secrete luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which act on the gonads to…
Neural regulation of prolactin secretion
Neural regulation of prolactin secretion involves complex interactions between hypothalamic dopamine neurons and various stimulatory and inhibitory neurotransmitters. The key hypothalamic dopamine (TIDA) neurons project to the pituitary gland and inhibit prolactin release through dopamine D2 receptors on lactotrophs. TIDA activity is regulated by prolactin feedback, estrogen, neurotensin, bombesin, glutamate, opioids, GABA, and other factors…
Neural regulation of cerebral blood flow
Neural regulation of cerebral blood flow is a complex process that involves coordination between neural activity, blood vessels, and metabolic factors. Here is a detailed summary based on the provided sources: Neural activity leads to increased cerebral blood flow to active regions through neurovascular coupling. When neurons are active, they utilize more oxygen and glucose,…
Fluid homeostasis of the ocular surface
The ocular surface comprising the cornea and conjunctiva must maintain adequate hydration for optical transparency and refractivity. Tear film covers the ocular surface, providing lubrication and nutrition while protecting against desiccation [1]. Tears are secreted by the lacrimal glands and distributed by blinking and drainage through the lacrimal apparatus [1][3]. The aqueous layer is secreted…
Reflex tear secretion
Reflex tear secretion is a fundamental protective mechanism of the ocular surface, triggered by a variety of stimuli that engage a complex neurocircuitry to elicit a rapid and graded lacrimal gland response. This process is distinct from basal and emotional tearing, relying on a well-defined reflex arc involving sensory afferents, central processing units within the…
Neural Regulation of Insulin Secretion
Insulin secretion from pancreatic beta cells is regulated by both nutrient and neural signals [1][2]. Vagal cholinergic signaling stimulates insulin release, mediated by muscarinic receptors on beta cells [2][6]. Gastrin and secretin also stimulate insulin secretion [1]. In contrast, sympathetic norepinephrine signaling inhibits insulin release via α2-adrenergic receptors [1][3]. Low blood glucose is sensed by…
Neural regulation of glucose homeostasis
Glucose homeostasis is tightly regulated by neural and hormonal signals. The pancreas secretes insulin and glucagon to control blood glucose levels [1][4]. Insulin secretion is stimulated by rising blood glucose levels as well as neural signals from the vagus nerve [2][3]. Insulin signals the liver, muscle and adipose tissue to take up glucose from the…
Neural regulation of growth hormone secretion
Growth hormone (GH) secretion from the anterior pituitary is primarily regulated by two hypothalamic hormones – growth hormone releasing hormone (GHRH) and somatostatin [1][2]. GHRH is secreted from the arcuate nucleus and stimulates GH release. Somatostatin is secreted from the periventricular nucleus and inhibits GH release [1][3]. The balance between GHRH and somatostatin signaling generates…
Neural regulation of metabolism
The hypothalamus and brainstem play key roles in regulating metabolism through both neural and hormonal signals [1][2]. The arcuate nucleus in the hypothalamus contains neurons that sense nutrients and hormones related to energy status, including leptin, insulin, and ghrelin [3][5]. These neurons project to other hypothalamic areas like the paraventricular nucleus to modulate appetite and…