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Biomedical subjects

L Hiripi

Publications and source records attributed to L Hiripi.

At least 37 records · Page 2Linked to original sources
PubMed1998

Sequence, structure and chromosomal localization of Crtm gene encoding mouse cartilage matrix protein and its exclusion as a candidate for murine achondroplasia.

The mouse cartilage matrix protein gene (Crtm) was isolated from a cosmid library using a mouse Crtm cDNA fragment as probe. Crtm spans 12.2 kb from the start of translation to the polyadenylation signal sequence and comprises eight exons. Sequencing of the 1.9 kb 5' flanking region revealed a TATA-like box 72 bp upstream from the initiator Met codon as well as several cis-acting motifs known to bind eukaryotic transcription factors. Analysis of the exon-intron junctions demonstrated that the last intron does not follow the gt/ag rule but belongs to the minor class of pre-mRNA introns that contain "at" and "ac" at their 5'and 3' ends, respectively. Single-strand conformation polymorphism analysis was used to map Crtm to the distal part of chromosome 4 between the microsatellite markers D4Mit16 and D4Mit339. Achodroplasia (cn), a recessive skeletal disorder in mice, has already been mapped to this region. Immunostaining for CMP and sequence of Crtm in cn/cn mice failed to reveal any disease-specific mutations, suggesting that mutations in Crtm do not cause achondroplasia.

Achondroplasia↗
PubMed1998

The organization of serotonin-, dopamine-, and FMRFamide-containing neuronal elements and their possible role in the regulation of spontaneous contraction of the gastrointestinal tract in the snail Helix pomatia.

The distribution of serotonin-, tyrosine hydroxylase-, and FMRFamide-immunoreactive neuronal elements, as well as the concentrations of serotonin and dopamine in the different parts of the gastrointestinal tract, were studied in the snail Helix pomatia. The sensitivity of the spontaneous contractions of the alimentary tract to serotonin, dopamine, and FMRFamide was also tested. Serotonin-, tyrosine hydroxylase-, and FMRFamide-immunoreactive elements could be demonstrated in each part of the gastrointestinal tract, but they showed different innervation patterns. Serotonin- and tyrosine hydroxylase-immunoreactive elements were dominant in the submucosal layer, whereas FMRFamide-immunoreactive elements were dominant in both the mucosal and submucosal layers. Tyrosine hydroxylase-immunoreactive elements were confined to the longitudinal muscle trabeculae of submucosa, whereas serotonin-immunoreactive elements were distributed throughout the submucosal layer. No serotonin-immunoreactive cell bodies, but only fibers, could be detected in the gastrointestinal tract, and therefore they represent extrinsic elements. Tyrosine hydroxylase- and FMRFamide-immunoreactive cell bodies represent intrinsic elements of the tract. The occurrence and density of the serotonin- and tyrosine hydroxylase-immunoreactive elements showed significant differences in the different parts of the alimentary tract, in accordance with HPLC assays, which revealed a significant frontocaudal decrease in both the serotonin (from 2.11 to 1.21 pM/mg) and dopamine (from 3.28 to 0.52 pM/mg) contents of the different parts of the alimentary tract. Dopamine at 10(-5) M concentration proved to be effective only on the longitudinal muscles by increasing the tone and frequency of contractions, but was ineffective on the circular muscles. Serotonin affected both the longitudinal and circular muscles. Serotonin at 10(-5) M concentration decreased the tone and increased the frequency of low-amplitude contractions of the longitudinal muscles of the esophagus and the gizzard but increased both the tone and frequency of the crop. Serotonin at 10(-9) M concentration slightly decreased the tone and blocked the contractions of the circular muscles in the crop but at 10(-5) M concentration induced contractions of the circular muscles in the gizzard. FMRFamide at 10(-6) M concentration decreased the tone and was shown to block the contractions of both the longitudinal and circular muscles.

Animals↗
PubMed1997

Octopamine-containing neurons in the alimentary tract of the earthworm (Eisenia fetida).

Octopamine-containing nerve cells have been demonstrated in the enteric plexus of the earthworm (Eisenia fetida), applying immunocytochemistry and HPLC assay. A few octopamine-immunoreactive neurons occurred in the fore- and hindgut, whereas their number in the midgut was considerably greater. Octopamine levels detected by HPLC correlated with the distribution of octopamine-containing nerve cells. A regulatory role for these intrinsic octopaminergic neurons is suggested in the enteric plexus in the earthworm alimentary tract. This is the first report on the occurrence of octopamine-containing nerve cells in the peripheral nervous system of an invertebrate.

Animals↗
PubMed1997

The effects of pesticides on monoaminergic system related to periodic activity of mussels (Anodonta cygnea L.).

1. The effect of a herbicide (paraquat) and an insecticide (methidation) on the periodic activity of mussel in relation to serotonin and dopamine levels and their release and uptake in nervous system was investigated. 2. LC50 values of methidation in 24-, 48-, and 96-hr treatments, respectively, were 50% lower than those of paraquat. 3. Serotonin and dopamine levels decreased in all three ganglia by 20% on average upon 24- and 48-hr in vivo treatments with paraquat. In the 96-hr treatment, however, both monoamines showed a 20-40% increase. With methidation treatment, the level of monoamines tested did not change significantly. 4. After paraquat treatment, both the average lengths of resting periods and their total duration significantly increased. Parallel to this, the average length of active periods and their total duration dramatically decreased. Methidation increased the average length and total duration of resting periods during the first 2 days at the expense of active periods. On the fourth day, however, the effect reversed: average length and total duration of active periods increased of the expense of parameters characteristic of the resting state.

Animals↗
PubMed1996

Cloning, sequencing and expression analysis of mouse cartilage matrix protein cDNA.

A cDNA encoding the mouse cartilage matrix protein (CMP) was cloned following the reverse-transcription polymerase chain reaction and rapid amplification of cDNA ends procedures using mRNA isolated from trachea. The open reading frame encodes a product of 500 amino acids. Large parts of the protein have been completely conserved when compared to chicken and human sequences, including all 12 cysteine residues of the mature CMP. In situ hybridization reveals an even distribution of the CMP mRNA in the developing skeleton, which is followed by a zonal distribution paralleling hypertrophy and calcification. From early cartilage differentiation and onwards, CMP transcript is absent in the forming articular surfaces and intervertebral discs. Extraskeletal expression of CMP mRNA was detected in the adult eye.

Amino Acid Sequence↗
PubMed1996

Octopamine in the developing nervous system of the pond snail, Lymnaea stagnalis L.

Development of the octopaminergic system in the pond snail, Lymnaea stagnalis, was investigated by means of immunocytochemistry and radioenzymatic assay. The earliest octopamine-immunoreactive neurons appear at a late embryonic stage (E85) of development following metamorphosis. At this moment of development, the adult-like pattern of distribution and projection (arborization) characteristics of octopamine-immunoreactive neurone can already be observed. During hatching and postembryonic (juvenile) development the number of labelled neurons increases only within the ventro-medial cell groups of the cerebral ganglia, whereas the extent of varicose axon arborization of the labelled neurons increases gradually. No peripheral projections of the embryonic and postembryonic octopamine-immunoreactive neurons were observed. The postembryonic increase in number of immunoreactive neurons and development of axonal arborization is accompanied by a rapid, exponential enhancement of octopamine content of Lymnaea CNS, as detected radioenzymatically. A possible role of the octopaminergic neurons in the regulation of certain physiological function(s), active only from a late stage of embryonic development, is suggested.

Animals↗
PubMed1994

Characterization of tyramine and octopamine receptors in the insect (Locusta migratoria migratorioides) brain.

The kinetic and pharmacological properties of [3H]tyramine and [3H]octopamine binding to membrane preparations of locust (Locusta migratoria migratorioides) brain were studied to characterize the tyramine and octopamine receptors. [3H]Tyramine and [3H]octopamine bind specifically and reversibly to the locust brain membrane with equilibrium achieved after 20 min. The dissociation of [3H]tyramine is monophasic while that of the [3H]octopamine shows a biphasic tendency. Scatchard analysis of the saturation curves reveals a single high affinity binding site for each of tyramine and octopamine. The mean (+/- S.E.M.) values of Kd and Bmax are 6.11 +/- 0.71 nM and 21.45 +/- 3.0 fmol/mg tissue for tyramine and 5.65 +/- 0.91 nM and 15.0 +/- 2.4 fmol/mg tissue for octopamine, respectively. Pharmacological analysis of the binding suggests the presence of both tyramine and octopamine receptors in the locust brain. alpha-Adrenergic agonists and antagonists have a high affinity to the octopamine but not the tyramine receptor whereas dopaminergic drugs have a higher affinity to the tyramine receptor than the octopamine receptor. No highly effective inhibitors of tyramine binding were identified. The serotonergic blockers, mianserin, LSD, BOL are effective blockers for both tyramine and octopamine receptors, whereas the serotonergic antagonist gramine is more active against the octopamine than the serotonin receptor. The results suggest that a G-protein binding mechanism is involved in the expression of both the tyramine and octopamine effects.

Adrenergic alpha-Agonists↗
PubMed1993

Characterization of the tyraminergic system in the central nervous system of the locust, Locusta migratoria migratoides.

Tyramine occurs in the central nervous system (CNS) of the migratory locust, Locusta migratoria migratoides. The distribution of tyramine within the CNS does not parallel that of octopamine. Tyramine is synthesised from tyrosine in the presence of tyrosine decarboxylase. A second decarboxylase in the CNS is active against 5HTP and DOPA. The locust ganglia incorporate tyramine by high- and low-affinity uptake processes that appear to be independent of dopamine and octopamine. Depolarisation of the locust ganglia by high potassium concentration results in calcium-dependent release of incorporated [3H]tyramine.

Animals↗
PubMed1993

Acetylcholine level in the brain and other organs of the bivalve Anodonta cygnea L. and its modification by heavy metals.

Acetylcholine was detected and measured in the ganglia (60-80 nmol/g), in the heart (10-15 nmol/g) and in the adductor muscles (4-5 nmol/g) of the bivalve Anodonta cygnea L. using gas chromatographic determination. Treatment of the animals with low concentration of heavy metals, which cause change in the behaviour, resulted in decrease of the brain acetylcholine level. Within 7 days treatment Cu2+ caused 80 per cent, Cd2+ and Pb2+ 30 per cent reduction with varying types of recovery after wash.

Acetylcholine↗
PubMed1993

Biochemical characterization of a serotonergic system in the neural sheath of Helix ganglia.

Seasonal alterations of serotonin (5HT) as well as the release of 5HT and the presence of the synthesizing enzyme of serotonin (5HTP-decarboxylase) were investigated in the neural sheath and desheathed ganglia of Helix pomatia. It has been established that i) serotonin concentration shows a seasonal variation in the sheath, ii) serotonin is not synthesized in the neural sheath, iii) K(+)-dependent serotonin release occurs only in the desheathed ganglia.

Animals↗
PubMed1992

Ultrastructural, biochemical and electrophysiological changes induced by 5,6-dihydroxytryptamine in the CNS of the snail Helix pomatia L.

The serotonin neurotoxin, 5,6-dihydroxytryptamine (5,6-DHT), was injected into the body cavity of snails. Changes induced in the central nervous system (CNS) by the neurotoxin were studied by morphological, electrophysiological and biochemical techniques for up to 90 days following injection. The neurotoxin induced a variety of ultrastructural alterations during the early phase (1st to 6th days) following treatment. On day 6 after treatment, membranous structures first appeared in the synaptic-like areas and apparently migrated to cell bodies where they were detected by day 14. Their number increased with time. Neurotoxin-induced structural alterations were found in neuronal processes and cell bodies of the serotonergic metacerebral giant cells injected intracellularly with horseradish peroxidase and in serotonin immunoreactive axons. These findings suggest that the toxin-induced alterations are rather selective for the serotonin-containing neuronal elements. The neurotoxin decreased the concentration of 5-HT in and [3H]5-HT uptake into cerebral and pedal ganglia, with a maximum effect between the 3rd and 5th day following drug administration. 5-HT levels and 5-HT uptake returned to normal by 19-21 days after treatment. The concentration of dopamine and of [3H]DA uptake capacity were reduced between 3-5 days after injection of 5,6-DHT by 6-7 days following treatment. The transmission from identified serotonergic synapses to targets was reduced beyond day 5 after 5,6-DHT administration. By 15 days after treatment, synaptic transmission between the metacerebral giant cell (MGC) and buccal followers was blocked. Transmission recovered by day 21 after 5,6-DHT. Comparison of the time-course of functional and structural recovery indicates that while functional recovery takes place within 21 days after treatment, certain structural alterations, e.g. the membranous structures and dense particles, remain in the nerve fibres and cell bodies. These may serve as specific intracellular markers of the serotonin-containing neuronal elements long after functional recovery from the effect of 5,6-DHT.

5,6-Dihydroxytryptamine↗
PubMed1991

Dopamine-immunoreactive neurones in the central nervous system of the pond snail Lymnaea stagnalis.

The distribution of dopamine and dopamine-immunoreactive neurones was studied in the central nervous system of the snail Lymnaea stagnalis. The results from immunocytochemical labelling were compared with those from the application of the glyoxylic acid fluorescence method and 6-hydroxydopamine-induced pigment labelling. Comparisons were also made between the number of dopamine immunoreactive neurones and the dopamine content of the ganglia, measured by high-performance liquid chromatography. Dopamine immunocytochemistry proved to be superior to the other two histochemical techniques in terms of specificity and sensitivity. The 6-hydroxydopamine-induced pigment labelling failed to prove a useful tool for the in vivo identification of all dopamine-containing neurones. The distribution and number of dopamine-immunoreactive neurones and levels of biochemically measured dopamine in specific ganglia showed a close correspondence. By using the results of the dopamine immunocytochemistry and glyoxylic acid technique, a detailed map of dopamine-containing neurones was constructed. Dopamine-containing inter- and intra-ganglionic axon tracts were also demonstrated. The mapping of dopamine-containing neurones will facilitate further neurophysiological analysis of dopaminergic neural mechanisms in Lymnaea.

Animals↗
PubMed1989

A comparison of four techniques for mapping the distribution of serotonin and serotonin-containing neurons in fixed and living ganglia of the snail, Lymnaea.

The distribution of serotonin and serotonin-containing neurons was studied in the ganglia of the CNS of the snail Lymnaea stagnalis. Results of the application of three different labelling techniques on wholemount preparations were compared with each other and with the serotonin content of the ganglia, measured by high-performance liquid chromatography. Serotonin immunocytochemistry resulted in the highest number of labelled neurons, but the more recently developed in vivo method of 5,6- or 5,7-dihydroxytryptamine-induced pigmentation also proved to be a reliable technique for the visualization of serotonin-containing cell bodies. In comparison with these two techniques, the glyoxylic acid fluorescence method appeared to be less sensitive. The distribution and number of serotonin-containing neurons and biochemically measured serotonin in specific ganglia showed a close correlation. By combining the results of the three labelling techniques, a detailed map of serotonin-containing neurons was constructed, and this was compared with maps of identified neurons prepared from earlier electrophysiological studies. Previously described serotonergic neurons were consistently found, as well as several new serotonin-containing cell types in the cerebral, visceral and parietal ganglia. A network of serotonin-containing inter- and intraganglionic axon tracts, and thin serotonergic fibres in the perineurium were also demonstrated. This in vivo and in vitro identification of serotonin-containing neurons will facilitate further neurophysiological analysis of serotonergic neural mechanisms in Lymnaea.

5,6-Dihydroxytryptamine↗
PubMed1987

Alterations of the serotonin level in the central nervous system of Locusta migratoria during larval-adult transformation.

Serotonin level was measured in the cerebral, suboesophageal, thoracic and abdominal ganglia of Locusta migratoria during larval-adult transformation. It has been established that the serotonin content shows a progressive increase in the period between the last larval stage and the first 7 days of adult life, being of the highest value in the abdominal ganglia (146%), followed by the thoracic (110%), and then by the cerebral and suboesophageal (75%) ganglia. No significant changes are manifested in the serotonin level in the course of moulting. Considerable increase is also detectable in the protein content of the ganglia during the studied development phase. No correlation is present between the protein and serotonin contents of the ganglia, the changes of the protein content was found to be faster as compared to that of serotonin.

Animals↗
PubMed1986

Effect of benserazid and 6-hydroxydopamine on the development of the last larval instar of the house cricket, Acheta domestica L.

The effect of benserazid and 6-OHDA on the duration of the last larval instar and development of wings with intact corpora allata and following allatectomy on Acheta domestica L. was studied. 6-OHDA failed to alter the duration of the last larval instar in the nymphs with intact corpora allata but prolonged it in the allatectomized crickets. Introduction of 6-OHDA in the second phase of the last larval instar caused a deformation of the wings both in allatectomized and intact crickets. Injection of benserazid to the nymphs of the last larval instar prolonged the duration of this phase only in the presence of the corpora allata. The effect of benserazid can be connected to elimination of central inhibition of the corpora allata involving dopaminergic neurons of the brain.

Animals↗
PubMed1984

Octopamine- and dopamine-sensitive adenylate cyclase in the brain of Locusta migratoria during its development.

Octopamine- and dopamine-sensitive adenylate cyclases were studied in the brain of Locusta migratoria during its metamorphosis. In the adult brain the effects of octopamine and dopamine on adenylate cyclase were additive, suggesting the presence of separate populations of adenylate cyclase-linked receptors for octopamine and dopamine. There are no separate receptors for noradrenaline. Octopamine stimulates adenylate cyclase in both adult and larval brain; however, in adult brain octopamine is more potent than in larval brain. Dopamine stimulates adenylate cyclase activity only in adult brain. The sensitivity of adenylate cyclase to octopamine changes during the development of the animal. Phentolamine and cyproheptadine are potent antagonists of octopamine-stimulated adenylate cyclase, while propranolol has a weak effect. No cytosol factor which would modulate either basal or octopamine-stimulated adenylate cyclase was found. The effect of GTP and octopamine on adenylate cyclase was synergistic in adult brain but not in larval brain, while the effect of GppNHp and octopamine was synergistic in both adult and larval brains.

Adenylyl Cyclases↗