Wyniki wyszukiwania

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Morphometrical studies of reproductive system of birds after treatment with dopamine receptor blockers and melatonin

100%

Dzerzhynsky M. E., Nuzhyna N. V., Vareniuk I. M.

Reproductive Biology

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2006

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tom 06

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nr Suppl.2

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Hypoxic ventilatory response in the rats with 6-hydroxydopamine lesion of the medial forebrain bundle and peripheral dopamine receptor blockade

84%

Andrzejewski K., Budzinska K.

Acta Neurobiologiae Experimentalis

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2013

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tom 73

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nr 1

The rat model of Parkinson’s disease (PD) based on experimental impairment of nigrostriatal dopaminergic system by 6-hydroxydopamine (6-OHDA) has been elaborated to study mechanisms of respiratory disturbances associated with PD. Following striatal injection of 6-OHDA breathing with hypoxic mixture augments the hyperventilatory response to hypoxia suggesting an attenuation of the depressant effect of dopamine on ventilation. In the present study we ask whether injection of 6-OHDA into the medial forebrain bundle (MFB), that evokes more severe motor symptoms, elicits changes in the hypoxic ventilatory response and whether changes in ventilatory response to hypoxia following the unilateral dopaminergic denervation are transmitted by peripheral dopamine D2 receptors. The experiments were performed on adult rats. Ventilatory parameters: tidal volume, minute ventilation, and frequency of breathing were measured with the use of body plethysmograph method before and two weeks following unilateral, double injection of 6-OHDA into the MFB. Changes in the body weight and behavioral cylinder test were evaluated at the same time points and compared with the results obtained in sham operated rats. Effects of peripheral dopamine D2 receptor antagonist, domperidone (1 mg/ kg i.p.) on ventilation during rest breathing and during 3 minutes exposure to hypoxia (8% O2)were studied before and after 6-OHDA injection. Two weeks after 6-OHDA treatment the cylinder test showed limb use asymmetry. Body weight increased less than in animals without 6-OHDA injection. Following the MFB lesion the hyperventilatory response to hypoxia was augmented mainly by an increment of tidal volume. Before the MFB lesion the pretreament with domperidone enhanced resting ventilation and hypoxic hyperventilatory response. After 6-OHDA injection domperidone no longer altered both normoxic breathing and the hyperventilatory hypoxic response. The study shows that an impairment of dopaminergic system by MFB lesion causes comparable changes in breathing and ventilatory response to hypoxia as lesions in the other locations of the nigrostriatal pathways. In 6-OHDA model of Parkinson’s disease changes in the hypoxic ventilatory response seem to be related to a reduction of peripheral D2 dopaminergic neurotransmission involved in the control of breathing.

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Immunohistochemical detection of prolactin in clinically non-functioning pituitary adenomas

84%

Winczyk K., Toszek J., Swietoslawski J., Wojtczak E., Pawlikowski M.

Folia Histochemica et Cytobiologica

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2020

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tom 58

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nr 2

4

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Vasopressin release in response to hypovolaemia in the conscious rat and the effect of opioid and aminergic receptor antagonists

84%

Peysner K., Forsling M. L.

Journal of Physiology and Pharmacology

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1991

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tom 42

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nr 3

Conscious rats were given i. p. polyethylene glycol (PEG) or dextran injections to compare their efficacy in inducing moderate hypovolaemia. Dextran was found unsuitable, producing large variability in the the plasma vasopressin (A VP) concentrations. Putative neurotransmitters involved in the A VP response to hypovolaemia and in basal release were examined using opioid, and ß-adrenoceptor and dopamine receptor-blocking agents. A dose of PEG was chosen to produce a decrease in blood volume of approx 14.5% giving plasma AVP concentrations of 19.0±4.6 pmol/1. Naloxone and phenoxy- benzamine failed to influence AVP release under both hypovolaemic and basal conditions. Prazosin also failed to influence the AVP response. In contrast propranolol elevated the plasma AVP concentrations in both conditions. Haloperidol enhanced basal AVP release but did not influence release during hypovolaemia. Guanethidine pretreatment partially blocked the response to hypovolaemia, but did not affect basal plasma AVP. Thus it appears that aminergic pathways have an inhibitory influence on AVP release under hypovolaemic and basal conditions. However, endogenous opioids do not appear to contribute significantly to the hypovolaemic response.

5

Cadmium modulates reactivity of central dopamine receptors in rats prenatally exposed to ethanol

84%

Felinska W., Brus R., Szkilnik R., Rykaczewska M., Plech A., Kostrzewa R. M., Frydrych J.

Polish Journal of Environmental Studies

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1995

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tom 04

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nr 1

Ethanol (EtOH) abouse in pregnancy is known to produce serious damage of internal organs of the fetus, a condition in humans that is classified as "fetal alcohol syndrome". Cadmium (Cd), a heavy metal pollutant of the environment, represents another toxin that produces retarded fetal growth and teratogenic effects. The developing brain is particularly sensitive to both toxins, being affected morphologically and neurochemically. Prenatal EtOH and Cd have been found to reduce endogenous dopamine (DA) levels and turnover in brain. To test whether reactivity of central DA receptors might be altered by prenatal EtOH and Cd, administered separately or jointly, rats were given 10% (v/v) EtOH and/or Cd (5 or 50 ppm) in their drinking water. Male offispring were tested at 3 months for behavioral effects known to be induced by agonists acting at different subtypes of DA receptors. A dose-effect curve demonstrated that SKF 38393-induced oral activity, primarily a DA D!-associated event, was not substantially altered in these rats. However, the dose-effect curve for quinpirole-induced yawning activity, primarily a DA D2/D3-associated event was reduced in the EtOH-exposed rats. This effect of EtOH was prevented by Cd, which alone had little effect on yawning activity. These findings indicate that prenatal EtOH exposure produces a diminished reactivity of receptors of the DA D2/D3 complex and that Cd prevents this effect of EtOH.

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The role of dopamine in the regulation of melatonin biosynthesis in vertebrate retina

67%

Zawilska J. B.

Acta Neurobiologiae Experimentalis

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1994

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tom 54

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nr S

7

Increased D1 and D2 dopamine receptor binding in the telencephalic feeding circuit of high feather pecking hens

67%

Kost'al L., Sedlackova M., Bilcik B., Kubikova L., Vyboh P., Keeling L.

Animal Science Papers and Reports. Supplement

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2005

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tom 23

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nr 1

Ograniczanie wyników

Morphometrical studies of reproductive system of birds after treatment with dopamine receptor blockers and melatonin

Hypoxic ventilatory response in the rats with 6-hydroxydopamine lesion of the medial forebrain bundle and peripheral dopamine receptor blockade

Immunohistochemical detection of prolactin in clinically non-functioning pituitary adenomas

Vasopressin release in response to hypovolaemia in the conscious rat and the effect of opioid and aminergic receptor antagonists

Cadmium modulates reactivity of central dopamine receptors in rats prenatally exposed to ethanol

The role of dopamine in the regulation of melatonin biosynthesis in vertebrate retina

Increased D1 and D2 dopamine receptor binding in the telencephalic feeding circuit of high feather pecking hens