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Biomedical subjects

P Eneroth

Publications and source records attributed to P Eneroth.

At least 181 records · Page 10Linked to original sources
PubMed1985

Cholecystokinin neuron systems and their interactions with the presynaptic features of the dopamine neuron systems. A morphometric and neurochemical analysis involving studies on the action of cholecystokinin-8 and cholecystokinin-58.

A unique role for CCK-58 compared to that for CCK-8 has been demonstrated in the modulation of central catecholaminergic mechanisms and neuroendocrine functions. It is of paramount importance to localize CCK-58 immunoreactivity within the brain in order to establish if separate CCK-58- and CCK-8-immunoreactive neuron systems exist. The two most significant actions of CCK-58 are a marked lowering of TSH secretion and a selective increase of DA turnover in DA-CCK co-existing synapses in the nucleus accumbens and tuberculum olfactorium.

Animals↗
PubMed1985

The effects of acute and chronic treatment with triiodothyronine and thyroxine on the hypothalamic and telencephalic catecholamine nerve terminal systems of the hypophysectomized male rat. Chronic treatment modulates catecholamine utilization in discrete catecholamine nerve terminal systems.

Using catecholamine (CA) fluorescence histochemistry in combination with quantitative microfluorimetry, it has been shown that chronic treatment with triiodothyronine (T3) and thyroxine (T4; 2 X 10 and 2 X 36 micrograms/kg i.p., respectively, twice daily for 10 days), but not acute treatment (1 and 3.6 mg/kg i.p., respectively, 2 h before killing), increases CA utilization in the medial and lateral palisade zones of the median eminence and reduces noradrenaline (NA) utilization in the parvocellular part and magnocellular part of the paraventricular hypothalamic nucleus of the hypophysectomized male rat. Following chronic T4 treatment it could also be shown that the CA levels in the medial and lateral palisade zones of the median eminence were increased, while the NA levels were reduced in the parvocellular part of the paraventricular hypothalamic nucleus. Chronic T3 treatment induced similar changes - increased CA levels in the medial palisade zone and reduced NA levels in the magnocellular part of the paraventricular hypothalamic nucleus. Within the telencephalon, chronic but not acute treatment with T3 or T4 selectively increased dopamine (DA) utilization within the diffuse type of DA nerve terminal systems of the nucleus accumbens. This action of chronic treatment of T3 or T4 was highly selective and no changes in DA levels could be demonstrated in any DA nerve terminals analyzed in the nucleus caudatus putamen; nucleus accumbens and tuberculum olfactorium. In all the experiments the TSH levels remained undetectable and the low basal serum prolactin levels were not modulated in any experimental group in spite of the treatment with a tyrosine hydroxylase inhibitor in the CA utilization experiments. Following 2-3 weeks after hypophysectomy, serum T3 and T4 were decreased by 30-50%. In the acute experiments with T3 or T4, serum T3 levels and T3 as well as T4 levels were markedly elevated after the respective treatments. In the chronic experiments, the T4 treatment resulted in significant increases in the serum levels of both T3 and T4. The present results indicate that discrete DA and NA nerve terminal systems within the median eminence (DA), nucleus accumbens (DA) and paraventricular hypothalamic nucleus (NA) can slowly respond to chronic treatment with T3 or T4. This effect is the result of a direct action of the thyroid hormones on the brain since TSH is absent in the hypophysectomized rat.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1985

Effects of chronic exposure to cigarette smoke on amine levels and turnover in various hypothalamic catecholamine nerve terminal systems and on the secretion of pituitary hormones in the male rat.

Male rats were exposed to the smoke from 2 cigarettes every morning for a total-period of 9 days. The next day they were decapitated immediately after the exposure to the smoke from 4 cigarettes (Kentucky reference IR-1 type) burned at 30-min intervals. Control animals were exposed to air alone or to nicotine-free cigarette smoke (Cambridge glass fibre filters). In contrast to chronic exposure to filtered smoke, exposure to unfiltered smoke resulted in a 10% increase in catecholamine (CA) levels (quantitative histofluorimetry) within the lateral palisade zone, the posterior periventricular hypothalamic nucleus and within the dorsomedial hypothalamic nucleus. There was also an increase in amine turnover (tyrosine hydroxylase inhibition by alpha-methyl-dl-p-tyrosine methylester; alpha MT) in the dopamine (DA) systems of the medial and lateral palisade zones and in the periventricular noradrenaline (NA) hypothalamic systems. Chronic exposure to unfiltered cigarette smoke resulted in reductions of prolactin, LH and FSH levels (radioimmunoassay). Following alpha MT treatment chronic exposure to unfiltered cigarette smoke still led to reduced prolactin serum levels. In addition an increased vasopressin serum concentration was found. The effects of chronic exposure to cigarette smoke on neuroendocrine function and on hypothalamic CA systems are suggested to be mediated via nicotine. Combined with the results from a previous study the present results indicate that tolerance does not develop with regard to the inhibitory effects of exposure to cigarette smoke on prolactin, LH and FSH secretions. The same is true for the stimulatory effects on the tubero-infundibular DA neurons and the periventricular NA systems. But chronic exposure to cigarette smoke seemed to induce tolerance with regard to its stimulatory effects on subependymal, dorsomedial and paraventricular hypothalamic NA systems and on corticosterone release.

Adrenocorticotropic Hormone↗
PubMed1985

Maternal and cord serum levels of tissue polypeptide antigen (TPA) in normal pregnancies.

The tumor antigen and cytoskeleton protein tissue polypeptide antigen (TPA) have been determined in maternal serum throughout pregnancy. TPA levels in serum from pregnant women (n = 70) were not different from those in nonpregnant women (n = 61) until pregnancy week 28, from which time levels increased until parturition. Duplex pregnancies (n = 7) had higher serum TPA concentrations than simplex pregnancies, which was significant in pregnancy weeks 28 (p less than 0.014) and 32 (p = 0.05). Maternal serum TPA concentrations did not change during abortion or parturition and the mixed umbilical blood concentration of TPA equaled that in the mother's serum just after parturition. The correlation between placenta weight and maternal serum TPA levels was significant (p = 0.025). The decline of TPA after labor indicated a t1/2 for serum TPA of 7.5 days.

Abortion, Induced↗
PubMed1985

Development of urinary concentrating capacity in weaning rats.

This study describes the development of the capacity to concentrate urine in 10- to 40-day-old rats that were normally weaned between 16 and 18 days, breast-fed until day 20, or abruptly weaned on day 16. Urine osmolarity after 24 h dehydration was significantly lower in 10- than in 20- and in 20- than in 40-day-old rats. The most pronounced increase occurred between 16 and 20 days in the three groups. The increase in urine osmolality was paralleled by an increase of papillary Na and urea concentrations. The length of the papilla increased linearly from day 10 to 40. Serum arginine vasopressin levels were not significantly different in dehydrated 10- and 20-day-old rats. Serum corticosterone increased significantly between 10 and 20 days of age in both normally weaned and breast-fed rats. The rise was accelerated between days 16 and 18 and paralleled the rise in urinary concentrating capacity. Adrenalectomy on day 16 abolished the increases in urine osmolality and papillary Na and urea concentrations, but not the growth of the papilla between days 16 and 20. The urinary concentrating capacity could be precociously induced by treatment with betamethasone from day 10 to 17 but not from day 17 to 20. Our results indicate that the accelerated development of urine concentrating capacity at the time of weaning is independent of dietary composition and most likely modulated by glucocorticoid hormones.

Adrenalectomy↗
PubMed1985

Effects of pup sucking behaviour on inhibition of sexual behaviour and ovulatory secretion of LH in lactating rats.

The time-interval between parturition and the display of sexual receptivity varied between 13.5 +/- 0.7 and 35.9 +/- 2.5 days in rats with litters of between 1 and 24 pups. Body weight gain decreased and the avidity of pup sucking behaviour, measured by the latency before the pups, placed on the ventrum of an anaesthetized mother, attached to a nipple of the mother, increased as litter size increased. Litter-shifting procedures, which introduced asynchrony between the lactational age of the mother and the age of the pups, produced deficiencies in sucking behaviour and did not prolong the time-interval between parturition and the display of sexual receptivity by the mother. By keeping the lactational age of the mother in synchrony with the age of the pups and depriving the pups of maternal contact and nutrition every alternate day, the time-interval between parturition and the display of sexual receptivity by the mother was prolonged by 17 days, the avidity of pup sucking behaviour markedly enhanced and the body weight gain of the pups retarded in comparison with mothers and pups continuously living together. The results show that the display of the first postlactational behavioural oestrus and surge of pituitary LH secretion can be greatly delayed by an increase in the avidity of pup sucking behaviour.

Animals↗
PubMed1985

Effects of restricted maternal contact in neonatal rats on sexual behaviour in the adult.

Rats, deprived of maternal contact and nutrition every alternate day starting on day 5 of life, attained a body weight at 45 days of age which was 50% of that of rats which had free access to maternal contact and nutrition. After 55 days of unrestricted food availability the body weight of the neonatally deprived rats was approximately 15% lower than that of the controls. Malnourished female rats showed normal behavioural oestrous cycles and became pregnant and lactated normally as young adults. After ovariectomy they showed higher lordosis quotients in response to treatment with oestradiol benzoate and progesterone than controls but lost less body weight in response to treatment with oestradiol-filled constant-release implants. Malnourished male rats ejaculated less frequently than controls in tests with sexually receptive female rats but this difference disappeared with repeated testing. The malnourished males showed longer ejaculation latencies and had somewhat higher serum concentrations of LH than controls after castration and treatment with testosterone-filled constant-release implants which reduced serum androgen concentrations to about 30% of the intact level. The results show that rats are capable of sustaining a rather severe neonatal nutritional deprivation without losing the capacity for essentially normal mating behaviour in adulthood.

Androgens↗
PubMed1985

Role of the uterine cervix in inhibition of sexual behaviour in lactating rats.

Treatment of ovariectomized rats with progesterone-filled constant-release implants, which increased serum progesterone concentrations to 99.4 +/- 5.0 nmol/l, facilitated the induction of lordosis behaviour by subsequent treatment with oestradiol benzoate (OB, 10 micrograms). Concurrent treatment with the dopamine receptor antagonist domperidone (two daily injections of 2.5 mg/rat), which increased serum prolactin concentrations, did not inhibit the behavioural response of ovariectomized progesterone-treated rats to OB. If the treatment was combined with stimulation of the uterine cervix it inhibited lordosis to a level which was comparable with that of progesterone-domperidone-treated rats, which had been ovariectomized and from which the pups had been removed on the day of parturition. The cervical stimulation did not increase the amount of prolactin secreted by the pituitary gland in response to an injection of domperidone. The behavioural effect of cervical stimulation was blocked by injecting an anaesthetic paste (0.1 ml lidocain-prilocain) intravaginally against the cervix. The effect of cervical stimulation, or of parturition, lasted only for a few days and sexual behaviour was inhibited during a prolonged period of lactation. Sucking by the pups on the nipples of the mother may be required for preventing sexual behaviour during the entire period of lactation.

Anesthesia, Local↗
PubMed1985

Pruritus during standardized mental stress. Relationship to psychoneuroendocrine and metabolic parameters.

The influence of experimentally-induced emotional stress on pruritic response of human skin was studied in healthy subjects. Experimental activation of the psychoneuroendocrine system was produced by standardized stressors, i.e. a colour-word-conflict test (Stroop-test) and a subsequent mental arithmetic problem. Pruritus was elicited by intradermal injection of histamine. Results obtained were compared with reported feelings of stress, and stress-induced physiological and biochemical changes. Reported stress levels were evaluated by a visual analogue scale. The physiological and biochemical observations included pulse rate, blood pressure, endocrine and metabolic parameters. The experimental model produced adequate psychoneuroendocrine stress reactions. Cutaneous responses to histamine remained despite this unaltered. The cutaneous responses were unrelated to reported stress levels as well as to physiological and biochemical variables prior to stressor exposure. The individual cutaneous reactions to stressor exposure were related to the adrenaline response pattern. Degree of control, ability to predict, and time limitation of the experimental situation may be important factors influencing the experimental outcome.

Adult↗
PubMed1984

Age-related differences in the serum prolactin response during standardized surgery.

The aim with the present study was to assess possible age-related differences in the serum prolactin, cortisol and blood glucose responses to standardized surgical stress in humans. Relatively healthy men suffering from inguinal hernias were selected. The subjects were divided into a group of younger people (M=36.4 years, r=23-45, n=7) and one of older people (M=66.5 years, r=56-75, n=9). Surgery was carried out under general anesthesia. Blood was drawn before, during and following the operation. Blood pressure and pulse rate were also monitored. No differences were noticed in plasma prolactin, cortisol, and blood glucose during basal conditions. Even though plasma prolactin increased significantly in both groups during surgery, it was higher in the younger group (M=56.2 micrograms/1) as compared with 28.7 micrograms/l for the older group, p less than .01. Plasma prolactin during surgery, but not under basal conditions, correlated inversely with age. No differences between groups were found during surgery in blood glucose and serum cortisol. This study indicates a diminished stress response in older subjects, possibly due to age-related neuroendocrine changes.

Adult↗
PubMed1984

Luteinizing hormone-releasing hormone increases dopamine turnover in the lateral palisade zone of the median eminence and reduces noradrenaline turnover in the nuc. preopticus medialis of the hypophysectomized male rat.

By means of catecholamine fluorescence histochemistry in combination with quantitative microfluorimetry the effects of luteinizing hormone-releasing hormone (LH-RH) has been studied on the amine levels and turnover in discrete catecholamine (CA) nerve terminal populations in the hypothalamus of the hypophysectomized male rat. LH-RH highly selectively increases dopamine (DA) turnover in the lateral palisade zone of the median eminence and highly selectively reduces noradrenaline turnover in the nucleus preopticus medialis without influencing amine levels in these CA nerve terminal systems. It is suggested that the ultrashort feed-back action of LH-RH involves increased release of DA in the lateral palisade zone leading to activation of the DA receptor inhibiting LH-RH release as well as a reduced noradrenaline release in the nucleus preopticus medialis leading to a reduced excitatory influence on the LH-RH neurons at the soma-dendritic level.

Animals↗
PubMed1984

Microbial findings in genital secretions from seven healthy fertile couples.

The bacterial genital flora in seven healthy couples was investigated three times during two consecutive menstrual cycles. From the females 53 species were cultivated and from the males 73 species. An average of 36, 24, and 25 species were isolated from cervical secretions on cycle day 7, 14, and 22, respectively. No correlation of bacteria was found between males and females investigated on the same day, arguing against a sexual exchange of the normal flora.

Adult↗
PubMed1984

IUD-induced changes in cervical secretion content of albumin, IgG and complement C3c.

Cervical secretion albumin, IgG, complement C3c, spinnbarkeit and amount of wet weight mucus recovered were analyzed in a group of 13 women using IUD as a contraceptive method and the results were compared to those obtained in a control group. Significant differences were obtained when concentrations and amounts of soluble proteins in the respective groups were compared, but spinnbarkeit and amount of wet weight mucus recovered were not affected by the presence of the IUDs.

Adult↗