Brain cannabinoids in chocolate.
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Amidohydrolases↗
Biomedical subjects
M Beltramo
Publications and source records attributed to M Beltramo.
Biosynthesis of an endogenous cannabinoid precursor in neurons and its control by calcium and cAMP.
Understanding the mechanisms involved in the biogenesis of N-arachidonoylethanolamine (anandamide) and N-palmitoylethanolamine is important in view of the possible role of these lipids as endogenous cannabinoid substances. Anandamide (which activates cannabinoid CB1 receptors) and N-palmitoylethanolamine (which activates a CB2-like receptor subtype in mast cells) may both derive from cleavage of precursor phospholipid, N-acylphosphatidylethanolamine (NAPE), catalyzed by Ca(2+)-activated D-type phosphodiesterase activity. We report here that the de novo biosynthesis of NAPE is enhanced in a Ca(2+)-dependent manner when rat cortical neurons are stimulated with the Ca(2+)-ionophore ionomycin or with membrane-depolarizing agents such as veratridine and kainate. This reaction is likely to be mediated by a neuronal N-acyltransferase activity, which catalyzes the transfer of an acyl group from phosphatidylcholine to the ethanolamine moiety of phosphatidylethanolamine. In addition, we show that Ca2+-dependent NAPE biosynthesis is potentiated by agents that increase cAMP levels, including forskolin and vasoactive intestinal peptide. Our results thus indicate that NAPE levels in cortical neurons are controlled by Ca2+ ions and cAMP. Such regulatory effect may participate in maintaining a supply of cannabimimetic N-acylethanolamines during synaptic activity, and prime target neurons for release of these bioactive lipids.
Amides↗
A confocal approach to the morphofunctional characterization of the transient tyrosine hydroxylase system in the rat suprachiasmatic nucleus.
The suprachiasmatic nucleus (SCN) of the neonatal rat is transiently innervated by tyrosine hydroxylase (TH) fibers of unknown origin and whose catecholaminergic nature is rather doubtful. In order to characterize this system morphofunctionally, immunocytochemical double labelling and confocal laser scanning microscopy analysis were employed on cryostat brain sections of 10-day-old rats. Simultaneous stainings for neuropeptide Y (NPY) and tyrosine hydroxylase (TH) immunoreactivity showed that they are not colocalized, neither in the SCN fibers nor in the intergeniculate leaflet (IGL) neurons, site of origin of the NPY projection to the SCN. Therefore, the possibility that SCN transient TH fiber system originates from the IGL could be excluded. Double labelling for TH and aromatic L-aminoacid decarboxylase (AADC) demonstrated that transient SCN TH immunoreactive (IR) fibers are AADC negative, thus supporting the hypothesis of their non-catecholaminergic nature. Moreover two new group of cells which are TH positive and AADC negative were found: one in the SCN and the other in the periventricular hypothalamic nucleus (PHN). The presence of somatostatin (SRIF) and TH in PHN neurons and SCN fibers suggested their possible colocalization, but double immunolabellings gave negative results. Simultaneous immunocytochemical staining for vasoactive intestinal polypeptide (VIP) and TH showed that TH fibers may interact with ventrolateral SCN VIP neurons. This result suggests a possible involvement of TH fibers in regulating VIP cells activity in the entrainment of circadian rhythms.
Animals↗
Confocal microscopy analysis of NPY and TH immunoreactivities in the hypothalamo-hypophysial system of the frog.
Co-expression of tyrosine hydroxylase (TH) and neuropeptide Y (NPY) in local circuits innervating the hypothalamo-pituitary complex of the green frog, Rana ridibunda, was investigated using simultaneous double immunohistochemical technique, aided by dual-channel confocal laser scanning microscopy. NPY and TH immunoreactivities were observed co-occurring within a discrete neuronal population located in the suprachiasmatic region. In other hypothalamic areas, NPY-immunoreactive (IR) perikarya were generally codistributed, but distinct from TH-IR cells. In the adenohypophysial pars intermedia, the overlap between the two markers was partial, demonstrating the existence of multiple neuronal sources for the inputs to the gland.
Animals↗
Immunolocalization of aromatic L-amino acid decarboxylase in goldfish (Carassius auratus) brain.
The distribution of monoamines (catecholamines and serotonin) in fishes has been previously studied by immunohistochemistry of both the monoamines themselves and their biosynthetic enzymes. But the distribution of neurons containing aromatic L-amino acid decarboxylase, an enzyme involved in the biosynthesis of both catecholamines and serotonin, has up to now not been investigated. In order to improve knowledge about the localization of aromatic L-amino acid decarboxylase, neurons containing this enzyme were mapped immunohistochemically in the goldfish brain. Furthermore, neurons bearing aromatic L-amino acid decarboxylase immunoreactivity have been compared with those containing tyrosine hydroxylase and serotonin immunoreactivities. Our results show that distribution of aromatic L-amino acid decarboxylase immunoreactivity generally coincides with that of tyrosine hydroxylase and serotonin. Nevertheless, the presence of nine D cell groups (containing aromatic L-amino acid decarboxylase but lacking both catecholamines and serotonin) and six groups of neurons which are aromatic L-amino acid decarboxylase-immunonegative but contain tyrosine hydroxylase, and might produce L-DOPA, have been revealed. The occurrence of both D cell groups and presumptive L-DOPA neurons in goldfish brain is discussed in relation to similar findings in fish and mammalian brain.
Animals↗
Postnatal development of the suprachiasmatic nucleus in the rat. Morpho-functional characteristics and time course of tyrosine hydroxylase immunopositive fibers.
According to earlier data, the suprachiasmatic nucleus of neonatal rats is highly innervated by serotonin- and tyrosine hydroxylase-immunopositive fibers [Ugrumov M. V. (1992) Zool. Sci. (Tokyo) 9, 37-45], while the latter were no longer observed in adults. This study has attempted to evaluate the timing of the innervation of the rat suprachiasmatic nucleus by tyrosine hydroxylase-immunopositive fibers, as well as to specify some morpho-functional characteristics of these fibers. According to our semi-quantitative light microscopic immunocytochemical data, few tyrosine hydroxylase-immunopositive fibers were observed in the suprachiasmatic nucleus as early as the second postnatal day. They highly increased in number neonatally reaching a maximum at the 10th postnatal day, and then decreased dramatically in adulthood. These data suggest either the provisional character of the tyrosine hydroxylase-immunopositive fibers themselves or the transient expression of tyrosine hydroxylase within permanent fibers. The tyrosine hydroxylase immunopositivity in the fibers points to their catecholaminergic nature, while the overlapping in the distribution of tyrosine hydroxylase- and serotonin-immunopositive fibers might also suggest the transient expression of tyrosine hydroxylase in serotoninergic neurons. In order to check this hypothesis, the neurotoxins of catecholamine- and serotoninergic neurons, 6-hydroxydopamine and 5,7-dihydroxytryptamine, were intraventricularly injected at the second postnatal day, while their effects were specified by the semi-quantitative immunocytochemistry eight days later. 6-Hydroxydopamine did not modify the content of tyrosine hydroxylase-immunopositive fibers in the suprachiasmatic nucleus. Conversely, the treatment with 5,7-dihydroxytryptamine resulted in a significant increase in the number of the tyrosine hydroxylase-immunopositive fibers, while reducing the amount of the serotoninergic ones.(ABSTRACT TRUNCATED AT 250 WORDS)
5,7-Dihydroxytryptamine↗
Aromatic amino acid decarboxylase (AADC) immunohistochemistry in vertebrate brainstem with an antiserum raised against AADC made in E. coli.
Aromatic L-amino acid decarboxylase (AADC) is involved in the biosynthesis of catecholamines and indolamines. AADC is present in the nervous system, in the chromaffin cells, and in non-neuronal tissues. We tested the capacity of a new polyclonal antibody, obtained by immunization of rabbits with a recombinant protein beta-galactosidase-AADC, to detect monoaminergic neurons in the brainstem as well as monoaminergic paraneurons in the adrenal medulla from goldfish, frog, skink, quail, and mouse. In the adrenal gland we found an immunoreactivity that was consistent with the distributions of the chromaffin cells previously reported. In the brainstem, groups of immunoreactive neurons and several labelled fibers were observed in the five species studied. The raphe region showed cell bodies and processes similar to those previously identified as monoaminergic by other authors. In addition, in medulla oblongata and isthmic tegmentum we found, in goldfish, skink, and quail, neuronal groups similar to mammalian D groups which contain AADC but are devoided of serotonin and catecholamines.
Adrenal Medulla↗
Cannabinoids and neuroprotection.
Cannabinoid compounds are endowed with pharmacological properties that make them interesting candidates for therapeutic development. These properties have been known since antiquity. However, in the last decade extremely important advances in the understanding of the physiology, pharmacology, and molecular biology of the cannabinoid system have given this field of research fresh impetus and have renewed the interest in the possible clinical exploitation of these compounds. In the present review we summarize the effects elicited, at the cellular level, by cannabinoids acting through receptor-dependent and receptor-independent mechanisms. These data suggest different ways by which cannabinoids may act as neuroprotective agents (prevention of excitotoxicity by inhibition of glutamate release, antioxidant effects, anti-inflammatory actions, etc.). The experimental evidence supporting these hypotheses are presented and discussed with regard to both preclinical and clinical studies in disease states such as cerebral ischemia, brain trauma, and Multiple Sclerosis.
Animals↗
[Cholecystectomy with laparoscopy and laparotomy. Analysis of the complications].
Laparoscopic cholecystectomy (LC) has been adopted by many as the treatment of choice for uncomplicated biliary lithiasis; since an increasing number of surgeons use LC even in complicated cases, we examined our series in order to see if this is the correct procedure. We report on the results of our first 252 LC and compare them with our latest 66 open cholecystectomies, in order to evaluate number and importance of postoperative complications. Besides we compare complications in patients below and over 60 years of age to verify if age bears any significance. We found no difference in frequency of complications among patients younger or older than 60; highly significant is, on the contrary, the difference in complications between the two procedures, the incidence being much lower in the laparoscopic one. We state that LC is a safe and effective procedure and suggest it as the method of choice for the treatment of any symptomatic gallbladder stone disease.
Adolescent↗