Oxytocin release

Vasopressin release is associated with sexual arousal and oxytocin release with orgasm. Oxytocin also may play a role in sexual satiety. (Murphy, et ah, 1987 reviewed Carter, 1992.)... 

Genital stimulation during parturition stimulates many aspects of maternal behavior, including attraction to amniotic fluid and forming a selective bond with an alien lamb. This is possibly mediated by stimulation of oxytocin release, and/or activation of afferent noradrenergic pathways in the olfactory bulbs (Poindron etal, 1988). 

Kramer MS, Cutler N, Feighner J, Shrivastava R, Carman J, Sramek JJ, Reines SA, Liu G, Snovely D, Wyatt-Knowles E, Hale JJ, Mills SG, MacCoss M, Swain CJ, Harrison T, HiU RG, Hefti F, Scolnick EM, Cascieri MA, Chicchi GG, Sadowski S, Williams AR, Hewson L, Smith D, Rupniak NMJ (1998) Distinct mechanism for antidepressant activity by blockade of central substance P receptors. Science 281 1640-1645 Landgraf R (1995) Intracerebrally released vasopressin and oxytocin measurement, mechanisms and behavioral consequences. J Neuroendocrinol 7 243-253 Landgraf R, Neumann I (2004) Vasopressin and oxytocin release within the brain a dynamic concept of multiple and variable modes of neuropeptide communication. Front Neuroendocrinol 25 150-176... 

Oxytocin (Pitocin, Syntocinon) causes milk release (letdown) by stimulating contraction of the myoepithelial cells of the milk ducts in lactating mammary glands this forces milk from the alveoli of the breast. Oxytocin release is stimulated by suckling and by auditory and visual stimuli, such as a baby s cry. Oxytocin is available as a nasal spray, which is used as an aid to lactation when milk ejection is impaired. 

Intravenous use of ethanol, while once widely employed to inhibit premature labor, is now of historical interest only. Ethanol inhibits oxytocin release from the pituitary and thus indirectly decreases myometrial contractility. Today, pz-adrenomimetics and magnesium sulfate have replaced ethanol for parenteral tocolysis. 

Riddle WJR, Scott AIF, Bennie J, et al Current intensity and oxytocin release after electroconvulsive therapy. Biol Psychiatry 33 839-841, 1993 Riedel WJ, Klaassem T, Deutz NE, et al Tryptophan depletion in normal volunteers produces selective impairment in memory consolidation. Psychopharmacology 141 362-369, 1999... 

Clarke G, Lincoln DW, Merrick LP (1979) Dopaminergic control of oxytocin release in lactating rats. J Endocrinol 55 409-420. 

Crowley WR, Shyr SW, Kacsoh B, Grosvenor CE (1987) Evidence for stimulatory noradrenergic and inhibitory dopaminergic regulation of oxytocin release in the lactating rat. Endocrinology 121 14-20. 

Parker SL, Crowley WR (1992) Activation of central D-l dopamine receptors stimulates oxytocin release in the lactating rat evidence for involvement of the hypothalamic paraventricular and supraoptic nuclei. Neuroendocrinology 56 385—392. 

Prostaglandin F2o(PGF2a) and oxytocin (released from both... 

The primary stimulus for oxytocin release is suclding. Stimulation of tactile receptors located around the nipples of the breasts initiates an action potential that propagates along afferent nerve fibers through the spinal cord and mid-bram to the hypothalamus. The cell bodies in the paraventricular nucleus are then stimulated, resulting in the episodic release of oxytocin. Stretch receptors in the uterus and possibly in the vaginal mucosa may also initiate action potentials in afferent nerve fibers that ultimately stimulate the release of oxytocin from the neurohypophysis. Estrogens enhance the response of oxytocin to these stimuli. The influence of other parts of the brain on the release of oxytocin has been reported emotional stress, for instance, inhibits lactation. 

Lang RE, Rascher W, Heil J. Unger T, Wiedemann G, Ganten D. Angiotensin stimulates oxytocin release. 

If increase in y causes a change in x, which tends to increase y, feedback is said to be positive in other words, a further signal output is evoked by the response it induces or provokes. This is intrinsically an unstable system, but there are physiologic situations where such control is valuable. In the positive feedback situation, the signal output will continue until no further response is required. Suckling provides an example stimulation of nipple receptors by the suckling child provokes an increased oxytocin release from the posterior pituitary with a corresponding increase in milk flow. Removal of the stimulus causes cessation of oxytocin release. 

Consider, for example, the milk-ejection reflex. This behavior may not normally be triggered by pheromones, but it can occur within seconds of the onset of suckling or exposure to stimuli, including odors, that have become associated with suckling (Wakerly, Clarke, Summerlee, 1994). Milk ejection in these circumstances would therefore seem to qualify as a released response. But because milk ejection is secondary to the hormonal effects of oxytocin released from the posterior pituitary, the response would seem to qualify as a primed effect. 

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