Biomedical subjects

G Croiset

Publications and source records attributed to G Croiset.

39 records · Page 3Linked to original sources

PubMedDate not supplied

Involvement of ACTH and MSH in active and passive avoidance behavior.

Intracerebroventricular injection of antiserum to alpha--MSH induces a weak reduction of passive avoidance latencies after administration prior to retention testing. Administration of antiserum to ACTH 1--24 induces a more marked effect in this respect, whereas injection of a combination of these antisera results in the strongest reduction of passive avoidance retention. No effect of this treatment is observed when these antisera are injected immediately after the learning trial. In active avoidance behavior a facilitation of extinction of the response is observed after intracerebroventricular administration of the antisera prior to each extinction session. This effect is comparable with the one observed in passive avoidance behavior. From these data it is suggested that ACTH and alpha-MSH play an important role in processes related to the retrieval of information stored in the brain.

Adrenocorticotropic Hormone↗

PubMedDate not supplied

Fornix transection: discrimination between neuropeptide effects on attention and memory.

Transection of the fornix and the stria terminalis completely blocks the inhibitory action of ACTH 4-10 on extinction of a conditioned avoidance response (CAR), whereas this effect of the vasopressin analogue des-glycinamide-lysine-vasopressin (DG-LVP) is not affected. These data indicate that the behavioral effect of DG-LVP may be localized to certain anatomical substrates, while ACTH 4-10 needs an intact limbic system as a functional substrate for its effect on avoidance behavior. This differential effect of fornicotomy may also be interpreted as a discrimination between the effects of these neuropeptides on attention or on memory consolidation. Additionally, transection of the fornix and the stria terminalis induces an increase in motor responsiveness to an electric footshock (EFS) and a facilitation of acquisition of a CAR.

Adrenocorticotropic Hormone↗

PubMedDate not supplied

Psychoneurogastroenterology: interrelations in stress-induced colonic motility and behavior.

Individual differences in behavioral and physiological response patterns to stress may contribute to vulnerability for stress-related illnesses such as functional gastrointestinal disorders. Animal models could give clues about specific individual determinants of intestinal reactivity to stress and stress-induced sensitization. Rats fitted with permanent electrodes on the proximal colon were exposed to a single session of foot shocks (10 x 6 s in 15 min, preshocked) or no shocks (control). Two weeks later, the preshocked group showed a significantly greater colonic spike burst response to a novel shock-prod stressor in the home cage than controls. The increase in burst frequency was positively correlated with the duration of active burying of the threatening prod in both experimental groups, but not with other behavioral components. Basal colonic burst frequency at rest was negatively correlated with the increase in burst frequency due to shock-prod stress in both groups, but the degree of sensitization in preshocked rats vs. controls was of similar magnitude in rats with low and high basal colonic burst frequency. The results indicate that colonic responsivity to stress is related to both basal motility status and individual coping strategies.

Animals↗