Suckling is a persistent stimulus to the adrenocortical system of the rat.

Walker, C.‐D.; Lightman, Stafford L.; Steele, Marianne K.; Dallman, Mary F.

doi:10.1210/endo.130.1.1309321

Cited by 128 publications

(97 citation statements)

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“…Changes in glucocorticoid receptor binding capacity within the hippocampus as observed in lactation (Meaney, Viau, Aitken & Bhatnagar, 1989) are being studied in our laboratories also during pregnancy (Johnstone et al 1997). However, the stress response is also reduced in adrenalectomized lactating rats (Walker et al 1992), so altered feedforward control mechanisms of the HPA axis could be involved. The pregnancy-related alterations in plasma levels of the sex steroids, oestrogens and progesterone, could alter hippocampal mineralo- (Carey, Deterd, de Koning, Helmerhorst & de Kloet, 1995) and glucocorticoid (Burgess & Handa, 1992) receptor binding, hypothalamic CRH expression (Douglas & Russell, 1994;Grino, H ery, Paulmyer-Lacroix & Anglade, 1995) and ACTH and corticosterone secretion (Viau & Meaney, 1991;Burgess & Handa, 1992).…”

Section: Discussionmentioning

confidence: 99%

“…Reduced reactivity of the maternal HPA axis may protect both the pregnant rat and her offspring from harmful excessive levels of glucocorticoids (for review, see Weinstock, 1997). During lactation, the activity and regulation of the HPA axis are altered in ways that are dependent on the presence or suckling of the young (Walker, Lightman, Steele & Dallman, 1992;Windle et al 1997). Thus, an increase in glucocorticoid secretion and a flattening of the diurnal rhythm in glucocorticoid secretion have been described (Stern, Goldman & Levine, 1973;Walker et al 1992;Fischer, Patchev, Hellbach, Hassan & Almeida, 1995).…”

mentioning

confidence: 99%

“…During lactation, the activity and regulation of the HPA axis are altered in ways that are dependent on the presence or suckling of the young (Walker, Lightman, Steele & Dallman, 1992;Windle et al 1997). Thus, an increase in glucocorticoid secretion and a flattening of the diurnal rhythm in glucocorticoid secretion have been described (Stern, Goldman & Levine, 1973;Walker et al 1992;Fischer, Patchev, Hellbach, Hassan & Almeida, 1995). In addition, secretion of ACTH from the anterior pituitary and, consequently, of cortisol (humans) and corticosterone (rats) from the adrenal glands is reduced during physical (Altemus, Deuster, Galliven, Carter & Gold, 1995;Walker, Trottier, Rochford & Lavall ee, 1995), ether (Lightman & Young, 1989;Walker et al 1992) and noise stress (Windle et al 1997), and in response to cardiovascular stimuli (Keller-Wood, 1996).…”

mentioning

confidence: 99%

“…Thus, an increase in glucocorticoid secretion and a flattening of the diurnal rhythm in glucocorticoid secretion have been described (Stern, Goldman & Levine, 1973;Walker et al 1992;Fischer, Patchev, Hellbach, Hassan & Almeida, 1995). In addition, secretion of ACTH from the anterior pituitary and, consequently, of cortisol (humans) and corticosterone (rats) from the adrenal glands is reduced during physical (Altemus, Deuster, Galliven, Carter & Gold, 1995;Walker, Trottier, Rochford & Lavall ee, 1995), ether (Lightman & Young, 1989;Walker et al 1992) and noise stress (Windle et al 1997), and in response to cardiovascular stimuli (Keller-Wood, 1996). Furthermore, there are indications of altered emotional behaviour in lactating rats (Hard & Hansen, 1984;Walker et al 1995).…”

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confidence: 99%

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Attenuated neuroendocrine responses to emotional and physical stressors in pregnant rats involve adenohypophysial changes

Neumann

Johnstone

Hatzinger

et al. 1998

The Journal of Physiology

341

244

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1. The responsiveness of the rat hypothalamo-pituitary-adrenal (HPA) axis and hypothalamo-neurohypophysial system (HNS) to emotional (elevated plus-maze) and physical (forced swimming) stressors and to administration of synthetic corticotrophinreleasing hormone (CRH) was investigated during pregnancy and lactation. In addition to pregnancy-related adaptations at the adenohypophysial level, behavioural responses accompanying the neuroendocrine changes were studied. 2. Whereas basal (a.m.) plasma corticosterone, but not corticotrophin (adrenocorticotrophic hormone; ACTH), levels were increased on the last day (i.e. on day 22) of pregnancy, the stress-induced rise in both plasma hormone concentrations was increasingly attenuated with the progression of pregnancy beginning on day 15 and reaching a minimum on day 21 compared with virgin control rats. A similar attenuation of responses to both emotional and physical stressors was found in lactating rats. 3. Although the basal plasma oxytocin concentration was elevated in late pregnancy, the stressinduced rise in oxytocin secretion was slightly lower in day 21 pregnant rats. In contrast to vasopressin, oxytocin secretion was increased by forced swimming in virgin and early pregnant rats indicating a differential stress response of these neurohypophysial hormones. 4. The blunted HPA response to stressful stimuli is partly due to alterations at the level of corticotrophs in the adenohypophysis, as ACTH secretion in response to CRH in vivo (40 ng kg¢, i.v.) was reduced with the progression of pregnancy and during lactation. In vitro measurement of cAMP levels in pituitary segments demonstrated reduced basal levels of cAMP and a lower increase after CRH stimulation (10 nÒ, 10 min) in day 21 pregnant compared with virgin rats, further indicating reduced corticotroph responsiveness to CRH in pregnancy. 5. The reduced pituitary response to CRH in late pregnancy is likely to be a consequence of a reduction in CRH receptor binding as revealed by receptor autoradiography.[ÁÂÇI]CRH binding in the anterior pituitary was significantly reduced in day 11, 17 and 22 pregnant rats compared with virgin controls. 6. Anxiety-related behaviour of the animals as revealed by the time on and entries into the open arms of the elevated plus-maze was different between virgin and pregnant rats with decreased number of entries indicating increased anxiety with the progression of pregnancy (except on pregnancy day 18). The emotional behaviour, however, was not correlated with the neuroendocrine responses. 7. The results indicate that the reduced response of the HPA axis to stressors described previously during lactation is already manifested around day 15 of pregnancy in the rat and involves physiological adaptations at the adenohypophysial level. However, alterations in stressor perception at higher brain levels with the progression of pregnancy may also be involved.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Attenuated neuroendocrine responses to emotional and physical stressors in pregnant rats involve adenohypophysial changes

Neumann

Johnstone

Hatzinger

et al. 1998

The Journal of Physiology

341

244

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“…Cortisol is normally released in a pulsatile manner (Ladewig, 1987); the plasma levels vary with diurnal rhythm (Walker et al, 1992). To minimize those factors in our study, each blood sample was taken at the same time of the day.…”

Section: Discussionmentioning

confidence: 99%

Efficacy of a diet containing caseinate hydrolysate on signs of stress in dogs

Palestrini

Minero

Cannas

et al. 2010

Journal of Veterinary Behavior

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The purpose of this randomized, double-blind, placebo-controlled trial was to evaluate the efficacy of a diet containing caseinate hydrolysate (CH) on signs of stress in 2 groups of dogs (defined as Anxious and Nonanxious), using physiological (serum cortisol and lysozyme, N:L ratios and heart rate) and behavioral parameters.From an initial group of 40 female Beagle dogs, ranging in age from 10 months to 4 years (mean 5 1.47 years; SD 5 0.53) belonging to a dog colony, 32 were selected for this study according to their level of anxiety. A group of 16 Anxious dogs and a group of 16 Nonanxious dogs were identified.A baseline period, aimed to obtain reference values of investigated parameters, preceded the experimental phase. Both groups (Anxious and Nonanxious) were divided into a treatment group, which received the diet containing CH, and a control group which received a placebo diet (PD). Anxious CH and PD groups were balanced for anxiety level. Each dog was evaluated 3 times a day at 4 weeks intervals (T1-T2-T3). Each evaluation lasted 2 days and involved a Reactivity Evaluation Form, a blood sampling, heart rate recording, and a 10-minute behavioral video recording. Results from Reactivity Evaluation Form scores showed that although at T1 Anxious dogs had significantly higher scores (Mann-Whitney test, P , 0.001) compared with Nonanxious dogs, no difference was found between Anxious dogs fed with CH diet and Nonanxious fed with PD or CH diet at T3. Behavioral observations evidenced some signs of improvement in Anxious dog fed with CH diet. Cortisol level significantly decreased in Anxious dogs fed with CH diet (Friedman test, P , 0.05). Individual differences in physiological measures of stress responses may have contributed to the large variability, making interpretation of these measures difficult. These results suggest that CH may be used as a functional ingredient alleviating stress in dogs.

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