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Biomedical subjects

G Racagni

Publications and source records attributed to G Racagni.

At least 199 records · Page 11Linked to original sources
PubMed1979

Relevance of GABA in the nigrostriatal system.

In conclusion, even though the mutual integration of intrastriatal circuits remains an open question, the electrophysiological and neurochemical approaches seem to provide valid support toward understanding the complexity of these systems. Recent findings seem to indicate that, besides a dopaminergic and cholinergic link, interactions between DA and GABA neurons may be operative within the striatum. An understanding of these functional interplays may facilitate future attempts aimed at clarifying the electrophysiological discrepancies concerning the inhibitory or excitatory action of DA on the target cells in this brain structure. Studies on the functional roles of pathways projecting from striatum to substantia nigra have indicated that these may be implicated in the regulation of nigral efferents to other brain nuclei and that they do control striatal DA activity through feedback mechanisms.

Animals↗
PubMed1979

Cerebral tumours induced by ENU; changes of adenylate cyclase activity in the tumour latency time.

Tumours of the nervous system have been induced by transplacental ENU. Until the fourth month of life the tumoural lesions appear as mixed glial proliferations or oligodendroglial foci. From the fourth month on they develop as glial micro- and macrotumours or as isomorphic and polymorphic oligodendrogliomas. The adenylate cyclase activity studied during these two distinct phases of tumour development was markedly reduced in brain tumours, independent of their cellular origin, compared with the level in the normal brain. On the other hand, the activity of the enzyme responsible for the synthesis of cyclic AMP is significantly increased during the first period of tumour development when early neoplastic proliferations are present.

Adenylyl Cyclases↗
PubMed1979

PGF2 alpha, thromboxane B2 and HETE levels in gerbil brain cortex after ligation of common carotid arteries and decapitation.

The effects of ligation of both common carotid arteries in the gerbil on the levels of PGF2 alpha, TXB2, HETE and of energy metabolites in brain cortex, have been investigated. Also, in the same experimental conditions the changes of cyclic AMP in brain cortex, cerebellum, striatum and hippocampus have been monitored. ATP, glycogen, glucose and phosphocreatine decrease whereas, lactate and cyclic AMP are enhanced in the ischemic brain, as previously reported. In contrast, levels of arachidonic acid metabolites are not modified. During ischemia following decapitation, instead, PGF2 alpha, and TXB2, show considerable increase.

Animals↗
PubMed1978

Genotype dependent response of morphine and methionine-enkephalin on the electrically induced contractions of the mouse vas deferens.

Analgesia and locomotor activity are genetically differentiated in C 57 and DBA mice. In fact, DBA strain, unlike C 57, is very sensitive to the analgesic effects of morphine. On the contrary, morphine elicits an increase of locomotor activity only in C 57 mice. We have used this genetic approach to study the in vitro response of vas deferens contractions to morphine and methionine-enkephalin. The results obtained are the following: 1. The percentage of morphine inhibition of the electrically evoked contractions of the longitudinal muscle of the vas deferens is greater in DBA strain, which is sensitive to the analgesic effects of morphine, than in C 57 mice in which morphine exerts a stimulating effect of the locomotor activity; 2. Met-enkephalin has been found to be more active than morphine on the same preparation; 3. The inhibitory effects of Met-enkephalin appear to be greater in C 57 than in DBA mice; 4. Different doses of Naltrexone are required to reverse the effects of morphine and Met-enkephalin; 5. Cumulative doses of Met-enkephalin and morphine induce different responses in the vas deferens of C 57 and DBA mice. The results emphasize the usefulness to study analgesic activity in these strains of mice.

Animals↗