1,722,250 research outputs found
How receptor mosaics decode transmitter signals. Possible relevance of cooperativity
No full textIt has been demonstrated that receptor–receptor interactions between G-protein-coupled receptors (GPCRs) occur at the plasma-membrane level. It has also been shown that clustering of GPCRs in aggregates or receptor mosaics (RMs) results in the reciprocal modulation of their binding and decoding characteristics. It is hypothesized that cooperativity plays an important part in the decoding of signals processed by RMs of GPCRs. Thus, the binding of the ligand at one receptor alters the likelihood of the same ligand binding at the next site, in the case of RMs, formed by identical receptors and/or by iso-receptors (receptors that bind the same ligand)
Development of computer-assisted simulation procedure to analyze receptor modulatory processes.
No full textMultiple intramembrane receptor-receptor interactions in the regulation of striatal dopamine D2 receptors
No full textAdenosine A(2A), group I mGlu and neurotensin receptors have been previously found to modulate the binding characteristics of dopamine D2 receptors in membrane preparations from rat striatum. In the present study it is shown that stimulation of different combinations of striatal A(2A), group I mGlu and neurotensin receptors induce different effects on the modulation of D2 receptor binding to those obtained when they are separately stimulated using maximal effective concentrations. In competitive inhibition experiments of dopamine versus the D2 receptor antagonist [3H]raclopride the addition of the A(2A) receptor agonist CGS 21680, the group I mGlu receptor agonist DHPG or neurotensin induced a decrease in the affinity of the high affinity state of the dopamine D2 receptors for dopamine. When added together CGS 21680 plus neurotensin induced the same effect as when administered alone, CGS 21680 plus DHPG induced a synergistic effect and DHPG plus neurotensin lost their modulating effect on D2 receptor binding. These results demonstrate the existence of multiple intramembrane receptor-receptor interactions in the regulation of striatal D2 receptors
Region-specific inhibition of potassium-evoked [3H]noradrenaline release from rat brain synaptosomes by neuropeptide Y-(13-36). Involvement of NPY receptors of the Y2 type
No full textThe effects of the Y2 receptor agonist neuropeptide Y NPY-(13-36) on the depolarization-evoked release of [3H]noradrenaline (NA) from synaptosomal preparations of the medulla oblongata, the hypothalamus, the hippocampal formation and the parieto-occipital cortex of the male rat were studied. NPY-(13-36) (0.1-100 nM) caused a concentration-related inhibition of the depolarization-induced release of [3H]NA in all areas studied, except the parieto-occipital cortex. The results indicate that NPY Y2 receptors are present on NA terminals in all areas studied, except the parieto-occipital cortex and inhibit depolarization-evoked [3H]NA release
Fattori comuni a colloquio interiore, altruismo, condizioni subcliniche di malattie mentali alla luce di evidenze biologiche e intuizioni di artisti
No full textIt is suggested that some unique human mental capabilities on one hand have been
crucial for the evolutionary success of Homo Sapiens and for the development of his
complex and so different social organizations, on the other hand have represented a
new target for mental diseases. Furthermore, it is put forward a new concept to describe
some cases of evolutionary maladaptation, namely the “mis-exaptation” concept, which
is derived from the Gould Vrba concept of exaptation (Gould & Vrba, 1982). The special
human mental capability considered in the present paper is the “inner speech”. As
it will be shown, too an intense inner speech not only is an obstacle to act (see below,
Shakespeare and Leopardi), but it may be also a fertile soil where mental disturbances
can germinate.
It will also be discussed the possible evolutionary value for the population of the
appearance in some subjects of mis-exadaptive traits related to the inner speech, namely
the altruistic behaviour and some subclinical forms of mental diseases. As a matter of
fact, data will be reported demonstrating a possible link between some cases of borderline
schizophrenia and bipolar depression with creativity.
Finally, a possible solution for the evolutionary-genetic paradox posed by altruism
and schizophrenia will be suggested on the basis of the cryptic genetic repertoire, which
is likely present in the Homo Sapiens and has a fundamental role for evolvability.
Whenever possible, a parallel analysis will be carried out between bio-medical data
and hypotheses and intuitions of philosophers and great novelists
Acute intermittent nicotine treatment counteracts the reduced proliferation of the neuronal precursor cells of the subventricular zone (SVZ) in aged rat brain
No full textDemonstration of NPY transmitter receptor mismatches in the central nervous system of the male rat
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