Cerebrospinal Fluid Levels of Acetylcholinesterase, Monoamines and Oxytocin during Labour, Parturition, Vaginocervical Stimulation, Lamb Separation and Suckling in Sheep

Abstract

Acetylcholinesterase (AChE) activity, and concentrations of monoamines, monoamine metabolites and oxytocin (OT) were measured in the cerebrospinal fluid (CSF) of sheep during late pregnancy, labour, parturition, vaginocervical stimulation, lamb separation and suckling. Concentrations of AChE, 4-hydroxy-3 methoxyphenylethan-1,2-diol (MHPG) and OT were significantly elevated during labour and parturition. OT levels were also significantly raised in cycling ewes given vaginocervical stimulation. Separation of the ewes from their lambs (0.5–2 h) caused significant increases in AChE and MHPG, but not in OT. During suckling, following reunion of the ewes and lambs, concentrations of AChE and OT were significantly raised. The dopamine metabolites 3,4-dihydroxyphenylacetic acid and homovanillic acid were significantly lower in CSF during late pregnancy than during parturition and post-partum. Intravenous injections of OT which produced high circulating levels of this hormone in plasma produced significant, but very small, increases in concentrations of OT in the CSF. Our results show that in the sheep, labour, parturition, suckling and vaginocervical stimulation provoke a release of OT in the brain similar to that in the peripheral circulation. Changes in CSF levels of AChE and MHPG during labour, parturition and lamb separation, but not during vaginocervical stimulation, may be related to stress or hypertension.

Food sharing is linked to urinary oxytocin levels and bonding in related and unrelated wild chimpanzees

“…provisioning) [43,45]. In mammals, lactation has been described as the primary form of food sharing [73], and is well known to be connected to peripheral and central oxytocin release in mammals [34,74]. This positive feedback circuitry is considered a key mechanism for bond formation between mother and infant [34,75].…”

Successful Induction of Lactation in a Barren Thoroughbred Mare: Growth of a Foal Raised on Induced Lactation and the Corresponding Maternal Hormone Profiles

“…Furthermore, the ability of mothers to display a well-adapted maternal behavior is also modulated by maternal experience gained at the first parturition [25]. A previous report demonstrated that latencies to accept suckling attempts by a foster foal were reduced markedly by VCS treatment [28], which presumably reflects the surge of oxytocin resulting from physical stimulation that is normally associated with parturition, such as in ewes [19,20,27]. Similarly, the mare also showed maternal behavior, such as licking, toward the orphan foal during VcS treatment in our present study.…”

Central and peripheral oxytocin profiles during milking in ewes

“…A possible relationship between central and peripheral oxytocin concentrations was previously proposed under various experimental conditions (INSEL, 1990;JONES;HARRIS, 1983;KENDRICK et al, 1986). Moreover, the co-localization of oxytocinergic neurons in the paraventricular nucleus of the hypothalamus and its projections is related to central and peripheral oxytocin concentrations, suggesting a functional relationship (INSEL, 1990;JONES;HARRIS, 1983;KENDRICK et al, 1986).…”

“…Moreover, the co-localization of oxytocinergic neurons in the paraventricular nucleus of the hypothalamus and its projections is related to central and peripheral oxytocin concentrations, suggesting a functional relationship (INSEL, 1990;JONES;HARRIS, 1983;KENDRICK et al, 1986).…”