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A Benelli

Publications and source records attributed to A Benelli.

49 records · Page 3Linked to original sources
PubMed1988

[Nle4,D-Phe7]alpha-MSH improves functional recovery in rats subjected to diencephalic hemisection.

Rats subjected to diencephalic hemisection were s.c. treated with alpha-MSH (20 micrograms/rat daily) or with [Nle4,D-Phe7]alpha-MSH (10 micrograms/rat every other day) for two weeks starting on day 3 after lesion. Apomorphine-induced (1 mg/kg s.c.) rotational behavior was studied on days 7, 14 and 21 after lesion, and a sensorimotor test battery was carried out on days 3, 10, 17 and 24 after lesion. [Nle4,D-Phe7]alpha-MSH greatly reduced rotational behavior and significantly improved sensorimotor performance. Histological studies showed that treatment with alpha-MSH and, even more markedly, with [Nle4,D-Phe7]alpha-MSH reduced the size of the lesion and the pseudoinflammatory reaction, and caused a marked proliferation and hypertrophy of astroglia. Binding studies showed that no supersensitivity of striatal dopamine receptors developed on the lesioned side of alpha-MSH- and [Nle4,D-Phe7]alpha-MSH-treated rats. The present results seem to further support the trophic role of MSH peptides on nerve tissue.

Animals↗
PubMed1988

Improved recovery of nigro-striatally hemitransected rats induced by (Nle4, D-Phe7)alpha-MSH: a central effect.

Rats were subjected to nigro-striatal hemitransection and then intracerebroventricularly infused with the potent and long-acting alpha-MSH analogue, (Nle4, D-Phe7)alpha-MSH, at two different doses (15 or 30 ng/h/rat), or with saline (0.6 microliter/h/rat), continuously for 14 days starting on day 2 after lesion. (Nle4, D-Phe7)alpha-MSH dose-dependently improved the sensorimotor deficit (postural asymmetry, impaired limb reflexes and coordinated limb use, signs of cortical and pyramidal lesion), reduced turning behaviour induced by apomorphine, and increased spontaneous motility in the open field. 3H-Spiperone binding showed that (Nle4, D-Phe7)alpha-MSH treatment caused a down regulation of the striatal DA receptors in the lesioned side, contrary to the supersensitivity developed by the corresponding receptors of saline treated rats. These results indicate that melanopeptides improve the functional recovery of nigro-striatally hemitransected rats, by an action at CNS level.

Animals↗
PubMed1986

Evidence that dopamine receptors identified by [3H]dopamine in the ventricles of guinea-pig heart are of DA2 type.

Apomorphine and LY 171555, but not SKF 38393 displaced [3H]Dopamine binding to membranes of guinea-pig heart. Domperidone and 1-sulpiride but not SCH 23390 competitively antagonize the [3H]Dopamine binding performed with 100 microM cold dopamine as displacer. In conclusion the DA2 receptor agonists and antagonists used are able to interfere with the receptors labelled by [3H]Dopamine in cardiac muscle.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1985

Regulatory effect of calcium on 3H-dopamine binding to guinea-pig heart membrane preparations.

The effects of various cations on the specific binding of dopamine to its recognition sites are described using guinea-pig heart membranes as a substrate. Only CaCl2 provoked a dose-dependent facilitatory effect, while KCl, NaCl and MgCl2 acted in the opposite sense. Moreover, Na2EDTA also had an inhibitory effect on dopamine binding and completely prevented the facilitatory action of CaCl2 on 3H-dopamine binding. This effect is partially counteracted by trifluoperazine but unaffected by verapamil. We can conclude from this that calcium seems to be essential to optimizing 3H-dopamine binding to cardiac membrane preparations.

Animals↗
PubMed1984

Dopamine receptors in the guinea-pig heart. A binding study.

The binding of dopaminergic agonists and antagonists to guinea-pig myocardial membrane preparations was studied using 3H-dopamine and 3H-spiperone as radioligand. 3H-Dopamine bound specifically to heart membranes while 3H-spiperone did not. A Scatchard analysis of 3H-dopamine binding showed a curvilinear plot indicating the presence of two dopamine receptor populations that we have termed high- (Kd = 1.2 nM, Bmx = 52.9 fmol/mg prot.) and low- (Kd = 11.8 nM, Bmx = 267.3 fmol/mg prot.) affinity binding sites, respectively. The characterisation of the high-affinity component of 3H-dopamine binding indicated that the binding is rapid, saturable, stereospecific, pH- and temperature-dependent, and displaced by dopaminergic agonists and antagonists known to act similarly in vivo. The finding that pretreatment with dibenamine (which has been described as an alpha-adrenoceptor irreversible blocker) did not affect the binding of dopamine to cardiac membrane preparations suggests that alpha-adrenoceptors and dopamine receptors have separate recognition sites in the heart. We conclude that 3H-dopamine binds to specific dopamine receptors in the heart of guinea-pigs.

Animals↗
PubMed1981

Effects of a salt of cholestyramine and 2-[4-(p-chlorobenzoyl)phenoxy]2-methyl propionic acid (alpha-1081) on biliary lipid secretion in rats.

1 Hypolipidaemic agents may increase biliary cholesterol in man, inducing a supersaturated bile. 2 To evaluate this possible side-effect, we have studied bile lipid secretion over a period of 8 h with intact enterohepatic circulation and 4 h with complete interruption in rats treated for two months with a salt of cholestyramine and 2-[4-(p-chlorobenzoyl)-phenoxy]2-methyl propionic acid (alpha-1081, 1.150 g/kg body wt., daily), cholestyramine (1.125 g/kg body wt. daily), procetofenic acid (25 mg/kg body wt. daily) and saline respectively (six rats for each group). 3 Cholesterol saturation index significantly (P less than 0.005) increased (from 0.21 +/- 0.01 to 0.39 +/- 0.09, mean +/- s.d.), in rats fed with procetofenic acid but it did not in alpha-1081- and cholestyramine-treated animals. 4 Procetofenic acid and, to a lesser extent, cholestyramine increased the bile flow. Procetofenic acid increased cholesterol secretion from 0.45 +/- 0.17 to 0.94 +/- 0.19 mumol kg-1 body wt. h-1 (mean +/- s.d.). 5 Cholestyramine increased both serum cholesterol and bile acid secretion from 0.45 +/- 0.17 to 0.68 +/- 0.10 and 25.8 +/- 9.48 to 39.96 +/- 6.68 mumol kg-1 body wt. h-1 respectively; alpha-1081, on the contrary, had no effect on bile lipid secretion. 6 These data suggest that alpha-1081 may be used as a new hypolipidaemic drug without any risk of increasing cholesterol in bile.

Animals↗
PubMedDate not supplied

Male sexual behaviour: further studies on the role of alpha 2-adrenoceptors.

The role of central alpha 2-adrenoceptors in male sexual behaviour was investigated by administering the selective agonist, guanabenz, and the selective antagonist, efaroxan, to both sexually experienced and sexually inexperienced male rats. In sexually experienced animals, guanabenz, at the dose of 1 mg/kg i.p., increased mount and intromission latencies (ML, IL), intercopulatory interval (ICI) and post-ejaculation interval (PEI), and reduced mount and intromission frequencies (MF, IF) and copulatory efficacy (CE). Efaroxan, at the dose of 10 mg/kg i.p., reduced ML and IL. In sexually inexperienced animals, guanabenz, at the dose of 1 mg/kg i.p., slightly reduced the percent of animals achieving ejaculation and increased PEI. Efaroxan, either at the dose of 3 or 10 mg/kg i.p., increased the percent of animals achieving ejaculation and--only at the dose of 10 mg/kg i.p.--reduced EL. Finally, in sexually experienced animals, efaroxan (10 mg/kg i.p.) prevented the effect of guanabenz (1 mg/kg i.p.). On the whole, these data further indicate that, in rats, male sexual behaviour is positively modulated by brain noradrenergic systems.

Adrenergic alpha-Antagonists↗
PubMedDate not supplied

Influence of oxytocin on feeding behavior in the rat.

Oxytocin, whether administered intraperitoneally (IP) (375-6,000 micrograms/kg) or intracerebroventricularly (ICV) (1-10 micrograms/rat), dose-dependently reduced food consumption and time spent eating and increased the latency to the first meal in rats fasted for 21 hr. Pretreatment with the oxytocin antagonist d(CH2)5Tyr(Me)-[Orn8]vasotocin (ICV 10 micrograms/rat) completely prevented the feeding inhibitory effect of an equal dose of ICV oxytocin, and per se increased food intake. Our data further support the hypothesis that oxytocin plays the role of neurotransmitter or neuromodulator in the CNS, and suggest that its involvement in a number of homeostatic systems may include appetite control.

Animals↗
PubMedDate not supplied

Effects of estrogens and oxytocin on the development of neonatal mammalian ovary.

The preservation and death of germ cells in the neonatal mammalian ovary are linked with the presence of hormones. Estrogens and oxytocin are present at birth in all mammalian vertebrates. The aim of this study was to examine their role in the development of the neonatal ovary and also in the preservation and death of germ cells in the neonatal period: apoptotic phenomena play a fundamental role in the control of their number. Female neonatal mice were treated at birth with estradiol monobenzoate or oxytocin and sacrificed after 5 days. The ovaries were sectioned in toto into semi-thin sections, in order to calculate their volume. Thin sections were also carried out to verify, under the transmission electron microscope (T.E.M.), the cells in apoptosis. The ovaries treated with the greater concentration of estradiol monobenzoate showed a volume that was significantly greater than that of the controls and a reduction of germ cells in apoptosis. The ovaries treated with oxytocin at all degrees of concentration had a volume significantly less than the controls and they also had a higher number of germ cells in apoptosis.

Animals↗
PubMedDate not supplied

Distribution of [3H]colchicine in brain and spinal cord areas following its intracerebroventricular or intra-spinal cord injection in rats.

Intracerebroventricular or intra-spinal cord (at lumbar level) injection of low doses of colchicine leads to irreversible urine retention. To learn whether colchicine induces this effect by diffusing from the sites of injection, we studied, using the above-mentioned routes of administration, the distribution of [3H]colchicine in brain and spinal cord areas as a function of time. The release of [3H]colchicine into the blood and its elimination via the renal route was studied as well. The results of these experiments show that after its intracerebroventricular injection, [3H]colchicine diffuses to brain areas that normally exert a facilitatory or inhibitory action on urine excretion but reaches the lumbar region in only modest amounts (0.02%). On the other hand, after its intra-spinal cord injection, [3H]colchicine remains at the site of injection, where the sacral micturition center is located. This suggests that intracerebroventricular or intra-spinal cord injected colchicine induces urine retention by exerting its action at two different levels of the neuronal pathway that regulates micturition, depending on the site of injection.

Animals↗