Search PubMed⌕ Search

Biomedical subjects

S Govoni

Publications and source records attributed to S Govoni.

At least 163 records · Page 9Linked to original sources
PubMed1984

Chronic ethanol changes opiate receptor function in rat striatum.

Ethanol produces supersensitivity of striatal delta-opiate receptor sites labeled by [3H]DADLE and [3H]etorphine. The impairment may be ascribed to the diminished enkephalin release detected in rat striatum after chronic ethanol consumption. On the contrary, a lower affinity of striatal mu-opiate receptors results after same ethanol exposure. In fact, the Kd values of [3H]Met-enkephalin and [3H]DHM are enhanced when measured in striata of ethanol-dependent rats. The diverse sensitivity of the various classes of opiate receptors to ethanol may be ascribed to different ethanol effects on enkephalinergic transmission.

Animals↗
PubMed1984

Chronic lead exposure differentially affects dopamine transport in rat striatum and nucleus accumbens.

Dopamine release and uptake were investigated in striatum and nucleus accumbens slices of rats chronically exposed to lead. No indication of altered endogenous dopamine release under basal or depolarized conditions was observed in both areas. On the other hand lead intoxication inhibited striatal dopamine uptake while stimulating it at the mesolimbic level. Cocaine binding, that is related to the uptake system, appeared to be down-regulated in the striatum and unaffected in the nucleus accumbens. The results suggest that chronic lead might interfere with dopaminergic transmission at the presynaptic level through specific and differential interactions with the uptake process depending on the area examined.

Animals↗
PubMed1984

Afferent fibers mediate the increase of met-enkephalin elicited in rat spinal cord by localized pain.

Met-enkephalin levels were measured in various spinal cord regions of rats chronically suffering from the inflammation of a single paw following a treatment with Freund's adjuvant. The results indicate that chronic localized pain induces a selective increase of met-enkephalin immunoreactive material (ME-IR) in the dorsal horn of the spinal cord segment which receives a direct projection from the inflamed paw. In order to gain information on the functional meaning of these data, either the plexus brachialis or the sciatic nerve were sectioned peripherally before inducing inflammation. Denervation prevented the increase of ME-IR concentration induced by the injection of Freund's adjuvant. Our observations suggest that chronic localized pain in a limb induces a change in ME-IR content which is selective for the spinal cord segment receiving a direct projection from the inflamed paw. This increase depends on an intact innervation.

Afferent Pathways↗
PubMed1984

Chronic lead treatment affects dopaminergic control of prolactin secretion in rat pituitary.

The effect of lead exposure on dopaminergic mechanisms regulating prolactin (PRL) secretion was studied in rats by measuring dopamine (DA) and dihydroxyphenylacetic acid hypothalamic concentrations and DA receptor density in the hypothalamus and pituitary of lead-exposed animals. [3H]Sulpiride was used as dopamine receptor ligand. A decrease of dihydroxyphenylacetic acid (DOPAC) hypothalamic concentrations and a decrease of DA receptor density in the pituitary are shown. The decreased [3H]sulpiride binding in the pituitary is consistent with the elevated serum PRL concentrations previously described in lead-exposed rats.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1984

Chronic dihydroergotoxine treatment affects the number of dopamine recognition sites in rat striatum.

Ergot derivatives have been proposed to have ameliorative effects in various pathological conditions where dopaminergic transmission is believed to be impaired, namely Parkinson's disease, amenorrhea-galactorrhea syndrome, and in the treatment of behavioural disturbances of the elderly. To get more insight into a possible involvement of a direct action of ergot derivatives on dopamine receptors we studied the effect of acute and chronic dihydroergotoxine (DHT) treatment on 3H-Spiroperidol and 3H-N-Propylnorapomorphine (3H-NPA) binding to rat striatal membrane preparations. The results are in favor of an interaction of ergot derivatives with dopamine recognition sites both after acute and chronic treatment.

Animals↗
PubMed1984

Caerulein peripheral injection: a study on the correlation with dopaminergic metabolism.

Immunocytochemical and electrophysiological studies indicate the existence of a functional relationship between Cholecystokinin (CCK) and dopaminergic transmission. In order to gain more information on this relationship, the effect of Caerulein, a CCK stable analogue, on rat spontaneous locomotor activity and on biochemical markers of dopaminergic transmission were measured simultaneously. The concentrations of 3,4-dihydroxyphenylacetic acid (DOPAC) and the spontaneous or K+ evoked release of dopamine were studied in rat striatum and nucleus accumbens immediately after testing for motor activity. An almost complete reduction in locomotor activity but not significant changes in DOPAC content and dopamine release were observed in rats injected with the peptide (0.25/microgram/Kg, intraperitoneally). DOPAC concentrations were slightly (30%) decreased by increasing 200 folds caerulein dose. In addition, a very minute dose of haloperidol (25 /microgram/Kg) potentiated the caerulein (0.25/microgram/Kg) induced hypomotility, while the parameters of dopaminergic metabolism were unaffected. Our results indicate the existence of a relevant pharmacological interaction between caerulein and dopamine antagonists, although it is not clear whether this interaction takes place at the dopamine terminals level.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1984

Differential effects of caffeine on dihydroxyphenylacetic acid concentrations in various rat brain dopaminergic structures.

The behavioural and neurochemical effects of caffeine were examined in rats. The intraperitoneal administration of different doses of caffeine significantly decreased DOPAC concentrations in striatum, hypothalamus and frontal cortex, but increased them in nucleus accumbens. These observations suggest that the effects of caffeine on the central nervous system (cns) are at least partially mediated through an interaction with the dopaminergic system.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1984

Hydrocarbons in hens injected with inactivated oil adjuvant vaccine.

The radioactivity of different organs and tissues of laying hens injected with inactivated oil adjuvant vaccine containing [n-1-14C] octadecane was measured. It was shown that the hydrocarbons injected with the vaccination diffuse in relatively short periods of time to all the tissues, especially to those of the organs with greater blood supply, and that the hydrocarbons are largely eliminated by means of the eggs.

Alkanes↗
PubMed1983

Immunoreactive met-enkephalin plasma concentrations in chronic alcoholics and in children born from alcoholic mothers.

Several experimental and clinical observations indicate that ethanol ingestion induces specific neurochemical modifications in the Central Nervous System. In particular, an involvement of endogenous opiates has been suggested in the case of alcohol addiction. In this light, the plasma concentrations of met-enkephalin immunoreactive peptides (ME-IR) have been measured in selected groups of chronic alcoholics and in children whose mothers were ethanol addicts. Both groups revealed a marked reduction of ME-IR plasma concentrations when compared with sex and age matched controls.

Adult↗
PubMed1983

Age related changes of enkephalin in rat spinal cord.

Met-enkephalin immunoreactive material content was found to be decreased in the cervical and thoracic segments of the spinal cord from rats aged 25 months as compared to young, 3-month-old, rats. No age-related variations were detectable at the lumbar level. Bio-Gel P 30 column chromatography of thoracic segment extracts indicates that the composition of the immunoreactive material is similar in the two age-groups investigated. At the thoracic level opiate receptor binding was also measured. Opiate receptor number is increased in the thoracic segments of the spinal cord from older rats. These age-related changes in immunoreactive Met-enkephalin content and opiate receptor number at spinal levels may contribute to determine an altered pain sensitivity during aging.

Aging↗
PubMed1983

Ethanol and dopaminergic systems.

Chronic ethanol consumption produces derangements of cell membrane structure, perhaps by changing membrane lipid content. This impairment leads to modification of membrane-related processes. In fact, after chronic ethanol exposure, an increase in striatal adenylate-cyclase activity occurs. On the other hand, dopamine is unable to further potentiate the production of cyclic AMP. This finding demonstrates that the dopaminergic receptor associated with adenylate-cyclase activity is affected by chronic ethanol treatment. In particular, the affinity of the dopaminergic receptor labelled by 3H-Spiperone is enhanced. In addition, the receptor-adenylate cyclase coupling system is impaired after chronic in vivo exposure of animals to ethanol.

Adenylyl Cyclases↗
PubMed1983

Decreased content of met-enkephalin-like peptides in superior cervical and coeliac ganglia of aged rats.

Enkephalin like peptides seem to have an important regulatory role at ganglia level. The aim of the present study is to investigate whether the content of enkephalin-like peptides in sympathetic ganglia is affected by the aging process. The results show that the enkephalin like peptides content is low in superior cervical and coeliac ganglia of aged rats (25 months). The age-related decrease of enkephalin content in these structures may be of importance in determining an altered sympathetic control during aging.

Age Factors↗
PubMed1983

Effect of suloctidil on dopaminergic transmission in various rat brain areas: possible uses as drug for the elderly.

Suloctidil is a drug used in the elderly endowed with a mechanism of action at neuronal level which has not been completely explored. The results of the present study indicate that acute treatment with suloctidil induces a decrease of serum prolactin levels and a decrease of 3,4-diidroxyphenylacetic acid concentrations in various rat brain areas. In addition, the repeated injection of small Suloctidil doses produces a down-regulation of dopaminergic receptors. These data suggest that Suloctidil has dopamino-mimetic properties in vivo. This pharmacological activity may be of importance in the clinical action of Suloctidil in the elderly.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1983

Characterization of stereospecific binding of 3H-(-) sulpiride, a selective antagonist at dopamine-D2 receptors, in rat CNS.

Sulpiride endowed with dopamine (DA)-antagonist properties, does not antagonize neostriatal DA-sensitive adenylyl cyclase activity either in vitro or in vivo. Sulpiride however is able to displace radioactive ligands, which label DA-receptors, from their specific binding sites. On these bases sulpiride has been proposed as a selective antagonist at dopamine-D2 receptors. We have characterized 3H(-) sulpiride stereospecific binding in various rat brain areas. In particular, 3H(-) sulpiride binding was found to be saturable, stereospecific and maximally enriched in the synaptic membrane fraction prepared from dopaminergic brain areas. Among a variety of compound tested only DA, DA-agonists and DA-antagonists were competitors for 3H(-) sulpiride specific binding sites. The results suggest that 3H(-) sulpiride may be an useful tool for the characterization and localization of dopamine D2-receptors.

Animals↗
PubMed1983

Changes of beta-endorphin and Met-enkephalin content in the hypothalamus-pituitary axis induced by aging.

The amounts of beta-endorphin- and Met-enkephalin-immunoreactive material are higher in the pituitary of aged rats. However, the aging process decreases the content of beta-endorphin-, but does not affect that of Met-enkephalin-immunoreactive material, in hypothalamus. Thus, it seems that the regulatory mechanisms in the two areas are differentially affected by increasing age. On the other hand, the pituitary increase of these peptides is in line with the assumption that in the elderly the hormonal response to stress is impaired.

Adrenocorticotropic Hormone↗