ACTH does not mediate divergent stress responsiveness in rainbow trout

Pottinger, T.G.; Carrick, T. R.

doi:10.1016/s1095-6433(00)00357-3

Cited by 41 publications

(35 citation statements)

References 18 publications

(13 reference statements)

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“…For example, CRH may be directly involved in the acquisition of a conditioned response (Croiset et al, 2000;Eckart et al, 1999;Wu et al, 1997). However, we have no evidence that there are differences in hypothalamic CRH secretion in the HR and LR lines -plasma ACTH levels are indistinguishable in the two lines during stress (Pottinger and Carrick, 2001b). In the CNS, selection for divergent stress responsiveness in the HR and LR lines of rainbow trout has resulted in regional divergence in brain monoaminergic activity.…”

Section: Discussionmentioning

confidence: 66%

Extinction of a conditioned response in rainbow trout selected for high or low responsiveness to stress

Moreira

Pulman

Pottinger

2004

Hormones and Behavior

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The NERC and CEH trademarks and logos ('the Trademarks') are registered trademarks of NERC in the UK and other countries, and may not be used without the prior written consent of the Trademark owner. AbstractTwo lines of rainbow trout (Oncorhynchus mykiss) that exhibit divergent endocrine responsiveness to stressors also display disparate behavioral traits. To investigate whether the high-responding (HR) and low-responding (LR) fish also differ in cognitive function the rate of extinction of a conditioned response was compared between the two lines. Groups of HR and LR fish were exposed to a paired conditioned stimulus (CS; water-off) and unconditioned stimulus (US; confinement stressor). After exposure to 18 CS-US pairings at least 70% of individuals of both lines acquired a conditioned response (CR), manifested as an elevation of blood cortisol levels on presentation of the CS only. Post-conditioning, the fish were tested by presentation of the CS at weekly intervals, for 4 weeks, with no further reinforcement and the extinction of the CR in the two lines was compared. The decline in mean plasma cortisol levels after exposure to the CS over successive tests suggested that the CR was retained for a shorter period among the HR (<14 days) than LR fish (<21 days). The frequency of individuals within each line whose plasma cortisol levels indicated a stress response when exposed to the CS was significantly greater among the LR than HR fish at 14 and 21 days with no HR fish falling into this category at 21 days. At 28 days post-conditioning, there were no HR fish and only three LR fish that were categorized as "stressed". These results suggest that there are differences in cognitive function between the two lines. Possible mechanisms underlying these differences are discussed.

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Section: Discussionmentioning

confidence: 66%

Extinction of a conditioned response in rainbow trout selected for high or low responsiveness to stress

Moreira

Pulman

Pottinger

2004

Hormones and Behavior

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“…In this experiment both the "vaccine and stress" group and the "stress and vaccine" group become oversensitive to administration of a weightadjusted dose of ACTH compared with the control group, and the oversensitivity increased with duration of the experiment. Few studies on ACTH sensitivity have been done on fish, however Pottinger and Carrick (2001) showed that two lines of rainbow trout selected for high (HR) and low (LR) responsiveness to a standard crowding test had different responsiveness to weight-adjusted dose of ACTH. The LR strain had significant lower production of plasma cortisol compared to HR strain.…”

Section: Discussionmentioning

confidence: 99%

“…Stimulation (ACTH) and dexamethasone (DEX) suppression test was conducted in accordance to previous study by Pottinger and Carrick (2001), with some minor modifications. Briefly, at pre-stress, 4 and 6 weeks after start of the experiment 12 fish per group (a total of 36 fish), were netted from their respective tanks, then anaesthetised (as described above), and injected intraperitoneally with 1 mg kg -1 dexamethasone (SigmaAldrich) in ethanol: phosphate-buffered saline (PBS; 1:3; 1μg μL -l ).…”

Section: Stimulation and Suppression Test Of Hpi-axismentioning

confidence: 99%

The effect of allostatic load on hypothalamic–pituitary–interrenal (HPI) axis before and after secondary vaccination in Atlantic salmon postsmolts (Salmo salar L.)

Iversen

Eliassen

2013

Fish Physiol Biochem

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The experiment consisted of three experimental groups; 1) "vaccine and stress", 2) "stress and vaccine" and 3) control. All groups have previously been vaccinated 6 months prior to the start of the experiment. At the start of the experiment the "vaccine and stress" group was vaccinated with Pentium Forte Plus for the second time (25.02.2008), and then given a daily stressor (crowding stressor, 267 kg m-3 in 15 min) for a period of four weeks. The "stress and vaccine" group was given a similar daily stressor for four weeks, and then vaccinated for the second time. The control group was neither stressed nor vaccinated a second time. The results indicates that a fish in the "stress and vaccine" group enters an allostatic overload type 2 due to oversensitivity to ACTH, a reduced efficient negative feedback system, with elevated baseline levels of plasma cortisol, and reduced immune response with pronounced effects on the wellbeing of the animal. The "vaccine and stress" group entered an allostatic overload type 1 response, with oversensitivity to ACTH and transient reduced efficient negative feedback system, but at the end of the experiment the fish had recovered. This study shows that if plasma cortisol becomes elevated prior to vaccination it could instigate an allostatic overload type 2 with dire consequences on animal welfare. To reduce the risk of compromising the animal welfare during commercial vaccination of salmon one propose to grade the fish minimum a week prior to vaccination, or grade simultaneously with vaccination. This could reduce the overall allostatic load during handling and vaccination, and secure a healthy fish, with intact immune response and improved animal welfare.3

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“…This is not entirely consistent with emerging data on differences between the lines in behaviour (Pottinger and Carrick, 2001a;Øverli et al, 2002) and in brain monoaminergic profiles (Øverli et al, 2001). A recent study suggests that the interrenal is the site at which HPI divergence is mediated in these lines (Pottinger and Carrick, 2001b) and that therefore differences in behaviour and brain neuroendocrinology can be explained in terms of direct effects of cortisol. The present data do not readily fit this hypothesis and the possibility that selection may have altered, for example, the chromaffin catecholaminergic response to stress must also be considered.…”

Section: Discussionmentioning

confidence: 99%

Divergence of endocrine and metabolic responses to stress in two rainbow trout lines selected for differing cortisol responsiveness to stress

Trenzado

Carrick

Pottinger

2003

General and Comparative Endocrinology

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Abstract. Rainbow trout (Oncorhynchus mykiss) of two lines selected for low (LR) and high (HR) cortisol stress-responsiveness were subjected to confinement for a period of 336 hours.Endocrine (plasma cortisol, hepatic cortisol binding) and metabolic (plasma glucose, lactate, amino acids; hepatic glycogen and alanine aminotransferase levels) indices of stress were measured at intervals in confined and unconfined fish of both lines. During confinement plasma cortisol concentration reached maximum values earlier in HR fish (2 hours) than in LR fish (6 hours) returning to control values within 336 hours in both lines. Paradoxically, although both HR and LR lines displayed a characteristic metabolic stress response, these changes were more pronounced in LR fish. Plasma glucose and lactate levels increased during confinement in both lines but to a significantly greater extent in LR fish. Confinement significantly elevated plasma amino acids to a greater extent in LR fish than in HR fish. Liver glycogen concentration was depleted most rapidly in LR fish but was significantly higher in confined fish of both lines than controls at the end of the experiment. No significant changes were observed in hepatic alanine aminotransferase activity during confinement. Confined fish of both lines displayed a decrease in hepatic cortisol receptor abundance within 24 h and this was more sustained in HR fish. The more pronounced disturbance of a broad range of indicators of stress in confined LR fish, compared to HR fish, throws doubt on the magnitude of the cortisol response being the primary driver of these differences.

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ACTH does not mediate divergent stress responsiveness in rainbow trout

Cited by 41 publications

References 18 publications

Extinction of a conditioned response in rainbow trout selected for high or low responsiveness to stress

Extinction of a conditioned response in rainbow trout selected for high or low responsiveness to stress

The effect of allostatic load on hypothalamic–pituitary–interrenal (HPI) axis before and after secondary vaccination in Atlantic salmon postsmolts (Salmo salar L.)

Divergence of endocrine and metabolic responses to stress in two rainbow trout lines selected for differing cortisol responsiveness to stress

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