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Biomedical subjects

U Höglund

Publications and source records attributed to U Höglund.

9 recordsLinked to original sources
PubMed1991

Effect of cerebral ischemia on hypotension-induced increase in plasma vasopressin and hepatic glycogen concentration in the rat.

The effect of cerebral ischemia on the vasopressin response to hemorrhagic hypotension and on the hepatic and muscular glycogen mobilization was studied in rats. The addition of cerebral ischemia to the hemorrhage required withdrawal of significantly more blood to lower mean arterial pressure (MAP) to 50 mmHg but not if combined with ganglionic blockade. The increase in plasma vasopressin concentration during hypotension was not significantly different in rats with and without concurrent cerebral ischemia. Ganglionic blockade blunted the vasopressin response. Thus cerebral ischemia in fact attenuated the vasopressin response to hemorrhage. One hour after the insult, the hormone concentration in rats exposed to combined cerebral ischemia and hemorrhagic hypotension without ganglionic blockade was still above control levels and higher than in all other groups. Concomitantly the hepatic but not the muscular glycogen concentration in these rats was significantly lower than in the other groups.

Animals↗
PubMed1989

Biochemical evidence for the GABA regulation of vasopressin levels in microdissected brain structures after servo-controlled hypotension.

Discrete brain structures were analysed for gamma-aminobutyric acid (GABA) and vasopressin content in normo- and hypotensive rats treated with the glutamic acid decarboxylase inhibitor, 3-mercaptopropionic acid (MPA) and the GABAA agonist muscimol. In the normotensive group treated with MPA only, the concentration of vasopressin increased in the supraoptic nucleus, indicating an inhibitory role for GABA. In the hypotensive group a rise in the vasopressin level in the nucleus of the solitary tract was detected and the GABA level decreased in the supraoptic nucleus. Muscimol decreased the concentration of vasopressin in the nucleus of the solitary tract. The changes in the concentration of vasopressin may be a result of increased or decreased activation of the GABAergic system. The results show that the GABA- and vasopressinergic systems somehow interact although the more precise way of action remains to be clarified.

3-Mercaptopropionic Acid↗
PubMed1989

Aging and sociosexual behavior in the male rat.

Senescent and young rats have been studied in a copulatory test and sociosexual approach test. The copulatory test was applied to investigate age-dependent changes in the copulatory capacity in the rat. The sociosexual approach test was used to describe motivational aspects of this behavior. Latencies, frequencies and durations of copulatory behaviors in the copulatory test and visits to various incentive animals in the approach test have been measured. Senescent rats had longer latencies and less frequencies of copulatory behaviors. In the approach test they showed less visits to the estrous female. Data were also subjected to a correlational analysis in order to relate the findings of the two tests. It is concluded that aged male rats differ from young ones in organizing their behavior in relation to time, are less social and have a less pronounced social preference pattern. In addition, the coherence between various elements of copulatory behavior was less in the senescent rat than in the young male rat, whereas the social approach patterns are more coherent in the aged male.

Aging↗
PubMed1988

Neonatal vasopressin antagonist treatment facilitates adult copulatory behavior in female rats and increases hypothalamic vasopressin content.

This study confirms that i.c.v. administration of Arg-vasopressin (AVP, 20 ng) inhibits copulatory behavior in female rats (lordosis response, LR) and demonstrates that this inhibitory effect is blocked by the vasopressin antagonist (3-mercapto-3-methylbutyryl-Tyr-[Me])arginine vasopressin (dPTyr(Me)AVP, 20 ng, i.c.v.). The effects of neonatal AVP antagonist treatment on adult female copulatory behavior, hypothalamic content of AVP and AVP-like immunoreactive (AVP-ir) neurons were examined. dPTyr(Me)AVP was given to female rats 1 microgram/animal/day s.c. from day 1 through to day 7 (day 0 = day of birth). The females were ovariectomized as adults and sexual receptivity activated by submaximal doses of estradiol plus progesterone. The LR was significantly facilitated in the neonatally dPTyr(Me)AVP treated females who also showed a higher content and an increased number of AVP-ir neurons in the suprachiasmatic nucleus compared to saline controls. Functional, biochemical and immunocytochemical evidence is provided that neonatal exposure to an AVP antagonist induces persistent changes in central vasopressinergic neuronal mechanisms.

Animals↗
PubMed1988

Dopamine mediated behavior and GABA influence.

The possibility of interactions between GABA and dopaminergic central nervous mechanisms in the expression of spontaneous behavior was investigated using the behavior pattern shown by male rats in an exploratory test situation. The present study corroborates the facilitatory action of low doses of the dopamine agonist apomorphine on the investigative activity element of the male rats exploratory behavior pattern, as shown previously. In addition it was found that the GABA agonist baclofen in different doses (1.2-4.8 mg/kg IP) selectively increased this activity. Pretreatment with a submaximal dose of baclofen (1.2 mg/kg) potentiated the effect of apomorphine (25 micrograms/kg), indicating that baclofen has the same effect on behavior as presynaptically active dopamine agonists. Thus GABA mechanisms might influence dopamine mediated behavior. The investigative activity which previously has been considered to reflect the adaptive state of an animal is suggested to be influenced by a changed activity in GABA neurons, DA neurons or an interaction between these two systems in the various brain structures involved in the expression of this behavior.

Animals↗
PubMed1988

Influence of ACTH1-24 on grooming and sociosexual behavior in the rat.

The effects of intraventricular administration of ACTH 1-24 on grooming, exploratory and socio-sexual behaviors in male rats were studied. The various behavioral elements were analyzed in terms of latency, frequency, and duration, which provided a multivariate behavioral profile. Behaviors that occur early during the test procedure had decreased, whereas behaviors displayed after the animal had spent some time in the test situation increased. Sociability, sexual approaches, and sexual preference in a sociosexual test situation were not altered by this treatment. The extinction of the response after removal of the incentive animals was delayed, however. It is concluded that ACTH1-24 did not specifically influence goal-directed behaviors. The obtained change in the behavioral profile, including the grooming pattern, rather suggest that ACTH1-24 affects mechanisms associated with attention and habituation.

Animals↗