E. Paglietti

Apomorphine and L-DOPA lower ejaculation threshold in the male rat.

Abstract The subcutaneous administration of apomorphine at the dose of 50 μg/kg to sexually experienced male rats decreased the number of penile intromissions necessary to reach ejaculation and accelerated the achievement of ejaculation. Similar results were obtained with the administration of L-DOPA (100 mg/kg IP) in animals pretreated with Ro 4-4602, a peripherally acting carboxylase inhibitor. The effect of apomorphine was prevented by pimozide (250 μg/kg), a specific inhibitor of dopamine receptors. The results suggest that a dopaminergic hyperactivity may be involved in premature ejaculation.

Inhibition of copulatory behavior in male rats by D-ALA2-Met-Enkephalinamide

Abstract D-Ala 2 -Met-Enkephalinamide (DALA), a synthetic analog of met-enkephaline resistant to enzymatic degradation, was injected intraventricularly to sexually experienced male rats paired with receptive females. A dose of DALA of 6 μg which did not influence spontaneous motor activity, completely suppressed the copulatory behavior of all animals tested. A dose of 3 μg significantly increase mounting and intromission latencies, but did not influence other measures of the copulatory behavior. The effect of DALA was prevented by naloxone (1 mg/Kg), a specific inhibitor of opioid receptors. The results suggest that enkephalins may play a role in the regulation of copulatory behavior.

Sleep induced by low doses of apomorphine in rats

The effect of apomorphine on the EEG of freely moving rats was studied. Apomorphine at the dose of 1 mg/kg caused stereotypy and a marked reduction of total sleep. On the contrary, acute subcutaneous administration of apomorphine at the dose of 100 microgram/kg, or less, markedly increased the amount of total sleep (corresponding mostly to synchronized sleep). Moreover, the infusion of apomorphine (80 microgram/kg/h) for 4 h doubled the duration of slow and REM sleep. The hypnotic effect of apomorphine was prevented by neuroleptics, such as pimozide, benzperidol and L-sulpiride, at doses which, per se, did not modify the EEG of the animals. These results suggest the existence in the CNS of DA receptors mediating sleep.

Benzodiazepine-induced voraciousness in cats and inhibition of amphetamine-anorexia

Abstract The effect of different benzodiazepines on food intake was studied in cats which had been trained to eat their daily food within 3 hours, under conditions in which emotional factors were not present. When benzodiazepines were administered (at a dose ranging from 0.1 to 3 mg/Kg) before feeding, they increased both the total amount of food eaten and also the rate at which food was injested. When they were administered at the end of the feeding period, these compounds made the animals resume eating voraciously. The order of decreasing potency of the benzodiazepines tested was: oxazepam, N-methyl-lorazepam, diazepam, chlordiazepoxide, pinazepam, medazepam. Oxazepam (3 mg/Kg) stimulated maximally the food intake, even when administered up to 12 hours before feeding. Finally, oxazepam antagonized the anorexigenic effect of d-amphetamine, but did not influence amphetamine-induced hyperactivity and stereotyped behavior.

HbH Disease in Sardinia: Molecular, Hematological and Clinical Aspects

In this study we have defined the molecular basis and correlated the clinical phenotype with the alpha-globin genotype in a large series of patients of Sardinian descent with HbH disease. The most prevalent molecular defect was the deletion of 3 alpha-globin structural genes most commonly the (--/-alpha 3.7) genotype (83.6%) and rarely the (--/-alpha 4.2) genotype (1.4%), followed in decreasing order of incidence by the combination of deletion alpha zero-thalassemia and initiation codon mutation of the alpha 2-gene (--/alpha NcoI alpha = 9.8%), deletion alpha zero-thalassemia and pentanucleotide deletion of IVS-I of the alpha 2-globin gene, (--/alpha HphI alpha = 3.3%) deletion alpha zero-thalassemia and initiation codon mutation of the alpha 1-gene (--/alpha alpha NcoI = 1.3%), a homozygous state for initiation codon mutation of the alpha 2-gene (alpha Nco alpha/alpha NcoI alpha = 0.7%). Patients with the (--/alpha thal alpha) genotypes showed severer clinical and hematological features as compared to those with the (--/-alpha) or those with the (--/alpha alpha thal) genotypes. The single patient with the (alpha Nco alpha/alpha Nco alpha) genotype had a clinical phenotype intermediate between HbH disease and the alpha-thalassemia carrier status. This heterogeneity depends on the fact that the alpha 2-globin gene produces 2-3 times alpha-globin chains than the alpha 1-gene and the single remaining alpha 1-like globin gene in the -alpha 3.7 chromosome has a compensatory increase in the alpha-globin chain output. alpha-Globin gene mapping of HbH disease patients may be useful for predicting the clinical outcome and to improve genetic counseling.

α-Thalassemia carrier identification by DNA analysis in the screening for thalassemia

Differentiation between heterozygous α‐thalassemia and several phenotypically resembling alleles at the β‐globin gene cluster such as coinherited δ‐ and β‐thalassemia or γδβ‐thalassemia is a critical step in genetic counseling. In this paper we report our experience in the identification of the α‐thalassemia carrier state using polymerase chain reaction (PCR)‐based methods, and the feasibility and simplification of screening for thalassemia using this approach. α‐Globin genotype was determined by PCR‐based method in 526 adult subjects with reduced mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH), normal hemoglobin A2 and F, and normal serum iron. To verify the reliability of the protocol used, in 68 of these subjects we performed globin chain synthesis analysis and in 101 we determined α‐globin genotype by Southern blot analysis. Five hundred twenty‐one (99%) of 526 subjects examined were identified as carriers of one or two α‐thalassemia alleles. The identification of the α‐thalassemia carrier state may be fast and accurate by PCR‐based method, avoiding other cumbersome and expensive methods such as globin chain synthesis and Southern blot analysis. Am. J. Hematol. 59:273–278, 1998.

Molecular pathology of haemoglobin H disease in Sardinians

We investigated the molecular basis for haemoglobin H disease in 50 Sardinian patients by restriction endonuclease analysis. We found that the majority (78% of the cases) are due to gene deletion (–/ ‐ α). Among those with a combination of deletion and nondeletion defects (–/ααth), the most prevalent nondeletion lesion (70% of the nondeletion defects) was the initiation codon mutation of the α2 gene (αNcoα), previously discovered in this population. Of the remaining patients with the (–/ααth) genotype, two showed the IVS‐1 splice junction lesion and one a mutation in the α1 gene, removing the Nco I site within the 5’part of the α1 gene, which may arise from a process of gene conversion from the initiation codon mutant of the α2 gene. A single patient had the homozygous state for the initiation codon mutant of the α2 gene. Study of genotype‐phenotype correlations indicates that the (αNcoα) haplotype is associated with a more severe defect in the α‐globin chain output than that resulting from the (‐α) haplotype. We may conclude that restriction endonuclease analysis is a powerful method for the definition of the molecular heterogeneity of haemoglobin H disease.

Genetic counseling and genetic heterogeneity in the thalassemias

In this study, we have compared the hemoglobin A2 levels (Hb A2) of α‐thalassemia carriers (‐α/‐α and ‐α/αα genotypes) with those of double heterozygotes for δ+ and β° thalassemia genes, who were identified by family studies and polymorphic restriction site analysis within the β‐globin gene cluster. We found that double heterozygotes for the δ+ and β° thalassemia have significantly (p<0.001) higher Hb A2 levels as compared with carriers of α‐thalassemia. This finding has practical implications in the genetic counseling of subjects with a thalassemia‐like phenotype associated with normal or borderline Hb A2 levels.

Human α-globin gene expression is silenced by terminal truncation of chromosome 16p beginning immediately 3′ of the ζ-globin gene

SummaryThe high level expression of the human α globin genes in erythroid tissue appears to require a set of DNaseI hypersensitive sites located upstream of the human α-globin gene cluster. These sequences, termed the locus control region (LCR), include two erythroid specific and a number of less restricted DNaseI hypersensitive sites. In this report we describe an individual with α-thalassemia associated with a truncation of the short arm of chromosome 16 that removes the LCR region and inactivates the adjacent intact α-globin genes. This genetic study supports the critical role of the LCR in the transcriptional activation of the human α-globin gene cluster and substantiates the importance of LCR deletions in the etiology of α-thalassemia.

Effect of psychotropic drugs on 3,4-dihydroxyphenylacetic acid (DOPAC) content in the medial basal hypothalamus

Abstract The effect of different psychotropic drugs on 3,4-dihydroxyphenylacetic acid (DOPAC) levels in the medial basal hypothalamus has been studied by the use of a very sensitive radioenzymatic method. Apomorphine and haloperidol, which are known to respectively decrease and increase DOPAC levels in the caudate nucleus, fail to influence DOPAC level in the medial basal hypothalamus. Reserpine, which increases DOPAC level in the caudate nucleus, decreases it in the medial basal hypothalamus. Amphetamine decreases DOPAC level in the medial basal hypothalamus as it does in the caudate nucleus. These results suggest that DA metabolism in the medial basal hypothalamus is controlled by mechanisms different from those operating in other brain areas.