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J Konopacki

Publications and source records attributed to J Konopacki.

47 records · Page 3Linked to original sources
PubMed1985

Ultrastructural markers of tubular transport in experimental diabetes insipidus.

Stereological analysis of changes in tubular transport markers in diabetes insipidus has been undertaken. Intracellular spaces and basal infolded channels were considered as the markers of water transport, while mitochondrial metabolic steady states were considered as the active transport markers. Transmission electron microscopic observations revealed morphometric differences in the surface area and volume of intercellular space and basal infolded channels in the distal tubules. Stereological markers of mitochondrial metabolic states demonstrated significant differences in the distal tubules between diabetes insipidus and control groups. In diabetes insipidus the volume and surface area of intercellular spaces and basal infolded channels in the distal tubules were decreased and the mitochondrial energy state was lowered.

Animals↗
PubMed1984

Effects of intraventricular injections of 6-hydroxydopamine on anterior pituitary cell proliferation.

Effects of intraventricular injections of 6-hydroxydopamine (6-OHDA; 200 micrograms/20 microliter vehicle) on anterior pituitary cell proliferation in rats have been investigated by means of the colchicine metaphase-arrest technique. In those groups of animals receiving 6-OHDA alone or 6-OHDA plus desmethylimipramine (DMI, 25 mg/kg body weight i.p.), where the mean mitotic activity rates (MMARs) were initially low at 48 hours, an increase of MMARs was observed at 96 and 144 hours after the drug injections. At 144 hours after drug administration, the MMARs values in the 6-OHDA-injected group and in the 6-OHDA + DMI-treated group were significantly higher than those in the control groups. This increase of MMARs resulted from the enhancement of acidophilic and chromophobe cell proliferation. The low MMARs at 48 hours after 6-OHDA injection are probably a result of dopamine release from damaged nerve endings; the enhancement of MMARs (particularly evident in the 6-OHDA + DMI-treated group) at 96 and 144 hours after drug administration is presumably related to a deficiency of dopaminergic control of anterior pituitary cell proliferation.

Animals↗
PubMed1984

Intraventricular 6-hydroxydopamine increases the adrenal cortex mitotic activity in rats.

Effects of intraventricular injections of 6-hydroxydopamine (6-OHDA) on adrenocortical cell proliferation in rats have been investigated by means of the colchicine metaphase-arrest technique. In the group of animals receiving 6-OHDA alone, an increase of mean mitotic activity rate (MMAR) was observed at 96 h and 144 h after injection. This rise of MMAR was completely inhibited by pretreatment of animals with desmethylimipramine (DMI) - a blocker of norepinephrine uptake. It is concluded that enhancement of ACTH secretion is responsible for the above mentioned increase of mitotic activity after 6-OHDA administration. This phenomenon is related to abolition of the inhibitory noradrenergic effect on ACTH secretion by 6-OHDA treatment. Additionally, the results suggest little or no involvement of dopaminergic neurons in early changes of ACTH secretion after intraventricular 6-OHDA.

Adrenal Cortex↗
PubMed1984

Motor activity and alimentary behavior after radio-frequency and 6-OHDA lesions of lateral hypothalamus and substantia nigra in cats.

Effects of radio-frequency lesions or injections of 6-hydroxydopamine (6-OHDA) into far-lateral hypothalamus (FLH) and substantia nigra (SN) on feeding behavior and motor activity were studied in four groups of cats. Hypoactivity, aphagia and adipsia followed by gradual recovery of alimentary behavior were observed only after radio- frequency lesions of FLH (group I). 6-OHDA injections into FLH evoked only slight and transient disturbances in regulation of fluid intake (group II). Radio-frequency destructions of SN produced long-lasting drop in drinking (group III) while 6-OHDA injections into SN caused long- lasting fall in food consumption (group IV). In both groups with SN damages different pattern of alimentary behavior was accompanied by motor hyperactivity.

Animals↗
PubMedDate not supplied

Effect of partial lesions of nucleus caudatus on food intake in cats.

The experiments were performed on 15 cats divided into 3 groups. In the animals from group I with lesions placed in the medial part of the head of caudate nucleus (NC), hyperphagia and hypodipsia developed. In the group II, with lesions in the ventral part of the head of NC, hyperphagia was observed. In the group III, with lesions in the dorsal part of the head of NC, hyperdipsia developed. These data indicate that caudate nucleus (NC) is a part of the system regulating food intake. Differentiation of disturbances following lesions placed in different areas of NC may be due to simultaneous damage of two opposite systems in which NC is included: the dopaminergic nigrostriatal system and the noradrenergic system.

Animals↗
PubMedDate not supplied

The effect of lesions of the dorsomedial thalamic nucleus on alimentary conditioned reflexes and food intake in dogs.

The experiments have been carried out on 6 dogs with type II conditioned alimentary reaction. After achieving the criterion in all animals the dorsomedial thalamic nucleus was destroyed by means of electrocoagulation. After the operation hypophagia developed with a rise in the number of intertrial responses and disinhibition of the alimentary conditioned reaction not exceeding 6 days. The obtained results confirm in part the hypothesis of Brutkowski who regarded this nucleus as belonging to a system controlling feeding behavior.

Animals↗
PubMedDate not supplied

Amphetamine anorexia in cats: the effect of encouraging to ingestive behavior.

The effect of encouraging to ingestive behavior was examined in cats pretreated with amphetamine (AMPH) in a dose sufficient for evoking anorexia (2 mg/kg). AMPH evoked complete refusing of spontaneous food ingestion in all animals. However, the cats could eat in even frantic manner when they were encouraged to ingestive behavior by moving the bowl with food around the place where the animal was sitting in the experimental cage. This result reveals that so called "anorexic syndrome" does not consist simply in a loss of appetite. It may be temporarily suppressed by some additional external stimuli which enable to channel the animal's behavior to the ingestive one.

Amphetamines↗
PubMedDate not supplied

Amphetamine anorexia: the effect of radio-frequency lesions and 6-OHDA injections into dopaminergic nigro-striatal bundle in cats.

The effect of radio-frequency (RF) and 6-OHDA lesions of two levels of dopaminergic nigro-striatal bundle on amphetamine anorexia was investigated in 4 groups of cats. RF and 6-OHDA lesions of far-lateral hypothalamus produced significant facilitation of feeding after injection of amphetamine. RF and 6-OHDA destructions of substantia nigra were with slight or without (respectively) effect on amphetamine anorexia. The results suggest that nigrostriatal bundle is not essential for mechanisms mediating amphetamine anorexia.

Amphetamine↗
PubMedDate not supplied

The role of dopaminergic nigro-striatal system in the aetiology of the lateral hypothalamic syndrome in cats: is there any deficit in thermoregulation?

Far-lateral hypothalamus (FLH) and substantia nigra (SN) were destroyed by radio-frequency current (RF lesion) or neurotoxically (6-hydroxydopamine injection) in 4 groups of cats. Hypothermia was observed only after 6-hydroxydopamine injections and RF lesions to FLH. Both methods of SN damage did not affect the body temperature of animals. These results suggest that hypothermia observed in LH syndrome in cats is not directly related to the function of the dopaminergic nigro-striatal system.

Animals↗
PubMedDate not supplied

The role of the dopaminergic nigro-striatal system in aetiology of the lateral hypothalamic syndrome in cats (II): behavioural responses to regulatory challenges.

Far-lateral hypothalamus ( FLH ) and substantia nigra (SN) were destroyed by means of radio-frequency current (RF lesion) or neurotoxically (6-hydroxydopamine injection) in 4 groups of cats. Deficits in osmoregulatory thirst were observed only after RF lesions of FLH . Disturbances in gluco-regulatory eating were observed after RF destructions and injections of 6-hydroxydopamine to the FLH . Both methods of SN damage did not affect the behavioural responses of the animals to regulatory challenges. These results suggest that deficits in behavioural responses to regulatory challenges observed in LH syndrome in cats are not related to the function of the dopaminergic nigro-striatal bundle.

Animals↗