Hyperalgesia and increased neuropathic pain-like response in mice lacking galanin receptor 1 receptors

The neuropeptide galanin may have a role in modulation of nociception, particularly after peripheral nerve injury. The effect of galanin is mediated by at least three subtypes of receptors. In the present study, we assessed the nociceptive sensitivity in mice lacking the galanin receptor 1 gene (Galr1) and the development of neuropathic pain-like behaviours after photochemically induced partial sciatic nerve ischaemic injury. Under basal condition, Galr1 knock-out (Galr1(-/-)) mice had shortened response latency on the hot plate, but not tail flick and paw radiant heat, tests. The mechanical sensitivity was not different between Galr1(-/-) and wild type (Galr1(+/+)) mice, whereas the cold response was moderately enhanced in Galr1(-/-) mice. Both Galr1(-/-) mice and Galr1(+/+) controls developed mechanical and heat hypersensitivity after partial sciatic nerve injury. The duration of such pain-like behaviours was significantly increased in Galr1(-/-). The Galr1(-/-) mice and Galr1(+/+) mice did not differ in their recovery from deficits in toe-spread after sciatic nerve crush. The results provide some evidence for an inhibitory function for the neuropeptide galanin acting on galanin receptor 1 (GALR1) in nociception and neuropathic pain after peripheral nerve injury in mice.

Molecular modelling and site-directed mutagenesis of human GALR1 galanin receptor defines determinants of receptor subtype specificity

Human galanin is a 30 amino acid neuropeptide that elicits a range of biological activities by interaction with G protein-coupled receptors. We have generated a model of the human GALR1 galanin receptor subtype (hGALR1) based on the alpha carbon maps of frog rhodopsin and investigated the significance of potential contact residues suggested by the model using site-directed mutagenesis. Mutation of Phe186 within the second extracellular loop to Ala resulted in a 6-fold decrease in affinity for galanin, representing a change in free energy consistent with hydrophobic interaction. Our model suggests interaction between Phe186 of hGALR1 and Ala7 or Leu11 of galanin. Receptor subtype specificity was investigated by replacement of residues in hGALR1 with the corresponding residues in hGALR2 and use of the hGALR2-specific ligands hGalanin(2-30) and [D-Trp2]hGalanin(1-30). The His267Ile mutant receptor exhibited a pharmacological profile corresponding to that of hGALR1, suggesting that His267 is not involved in a receptor-ligand interaction. The mutation Phe115Ala resulted in a decreased binding affinity for hGalanin and for hGALR2-specific analogues, indicating Phe115 to be of structural importance to the ligand binding pocket of hGALR1 but not involved in direct ligand interaction. Analysis of Glu271Trp suggested that Glu271 of hGALR1 interacts with the N-terminus of galanin and that the Trp residue in the corresponding position in hGALR2 is involved in receptor subtype specificity of binding. Our model supports previous reports of Phe282 of hGALR1 interacting with Trp2 of galanin and His264 of hGALR1 interacting with Tyr9 of galanin.

Personality disorders and the interpersonal octagon

The interpersonal octagon is a theoretical structure, similar to the interpersonal circle, within which a person's relating tendencies can be defined. It is constructed around a horizontal axis, concerning relating either closely or distantly, and a vertical one, concerning relating either downwardly or upwardly. The Person's Relating to Others Questionnaire--Revised Version (PROQ2) was designed to measure relating within the octagon. To test the validity of the proposed location of the 10 DSM-IV personality disorders within the octagon, the PROQ2 was administered, together with the DSM-IV version of the Personality Diagnostic Questionnaire (PDQ-IV), to a series of 107 men admitted to a therapeutic prison. The mean PROQ2 scores of the prisoners fell mid-way between those of male students and psychotherapy patients. High intercorrelations were found between the scale scores of both the PROQ2 and the PDQ, and there was a high correlation between total scores of the two instruments. All disorders were highly correlated with the lower close scale of the PROQ2. The locations of some disorders corresponded well with the pre-study predictions, and those of others came close. Those of a few came far from what was predicted, and some explanations for this are offered.

Institutional behaviour and time in treatment among psychopaths admitted to a prison-based therapeutic community

Previous research has indicated that psychopathy is associated with high levels of institutional misconduct and high attrition rates in therapeutic communities. However, most of this work has been conducted with North American populations. In the present study, data is presented on institutional behaviour and time in therapy for 104 inmates admitted to Grendon Therapeutic Prison. The results indicated that high scores on the Hare Psychopathy Checklist Revised were significantly associated with failure to progress from the assessment unit onto a therapy wing and the number of adjudications and security information reports. A trend was found for psychopathy to be associated with shorter periods in therapy, but this just failed to reach significance. The results confirm previous research on the association between psychopathy and institutional misconduct and provide some support for the association between psychopathy and early termination of treatment in therapeutic communities. A number of methodological issues are discussed.

Conservation of expression of neuropeptide Y5 receptor between human and rat hypothalamus and limbic regions suggests an integral role in central neuroendocrine control

Neuropeptide Y receptors belong to the G-protein-coupled receptor superfamily and mediate a wide variety of physiological functions, including blood pressure regulation, hormone release, appetite control, seizure propensity, cognition, and emotion. The recent description of a new neuropeptide Y receptor, Y5, expressed in hypothalamic nuclei in rat brain, raised the possibility that Y5 was the receptor mediating the feeding and appetite-related functions of neuropeptide Y. This was supported by subsequent data showing a downregulation of this "feeding" receptor in the brain of the obese Zucker rat (Widdowson, 1997). We have performed a detailed analysis of Y5 expression in rat brain using in situ hybridization histochemistry with digoxygenin-labeled riboprobes and compared this to expression of Y5 in human brain regions. mRNA for the human Y5 receptor was highly expressed in human hypothalamic and thalamic nuclei. In particular, the arcuate and paraventricular nuclei of the hypothalamus, midline thalamic nuclei, and amygdala showed very high levels of expression with high levels in hippocampus. The striking conservation of expression of the rat and human Y5 receptors in relevant hypothalamic and other nuclei implies sharing of a major neuroendocrine functional role by this receptor.

Galanin and galanin receptors

The development of a strain of galanin knockout mice has provided confirmation of a neuroendocrine role for galanin, as well as supporting results of previous physiological investigations indicating a role for galanin in analgesia and neuropathic pain, and potentially in neuronal growth and regeneration processes. Whether elevation of galanin expression in neurodegenerative disorders such as Alzheimer's disease represents a survival response or exacerbates functional deficit in afflicted individuals remains to be determined. More detailed analysis of the phenotype of the galanin knockout mouse should provide insights into the physiological role of galanin in memory and learning processes, as well as in hypothalamic function and other aspects of neuroendocrine regulation. Biochemical and molecular cloning efforts have demonstrated that the multiplicity of actions of galanin is matched by complexity in the distribution and regulation of galanin and its receptors. A focus on characterisation of galanin receptors has resulted in the molecular cloning of three receptor subtypes to date. The distribution and functional properties of these receptors have not yet been fully elucidated, currently precluding assignment of discrete functions of galanin to any one receptor subtype. It is not currently possible to reconcile available pharmacological data using analogs of galanin and chimeric peptides in functional assay systems with the pharmacological properties of cloned receptor subtypes. This highlights the value of further knockout approaches targeting galanin receptor subtypes, but also raises the possibility of the existence of additional receptor subtypes that have yet to be cloned, or that receptor activity may be modulated by regulatory molecules that remain to be identified. The development of receptor subtype-specific compounds remains a high priority to advance work in this area. The ability to selectively modulate the many different actions of galanin, through a clearer understanding of receptor structure-function relationships and neuronal distribution, promises to provide important insights into the molecular and cellular basis of galanin action in normal physiology, and may provide lead compounds with therapeutic application in the prevention and treatment of a range of disorders.

Distribution and characterization of the cell types expressing GALR2 mRNA in brain and pituitary gland

The neuropeptide galanin mediates its activities through G-protein-coupled receptors, and three receptor subtypes have been described with distinctly different patterns of regional tissue expression. GALR1 is predominantly expressed in basal forebrain, hypothalamus, as well as spinal cord. GALR2 has a wider distribution in brain and is also present in the pituitary gland and peripheral tissues. GALR3 has been found to be widely distributed at low abundance. We examined the distribution of GALR2 in rat brain and pituitary by in situ hybridization histochemistry and found it abundant in regions of hippocampus, piriform and entorhinal cortex, basal nucleus of the accessory olfactory tract, amygdala, hypothalamic nuclei, Purkinje cells, and discrete brainstem nuclei. It is also highly expressed in the intermediate and anterior lobes of the pituitary. Using combined in situ hybridization immunohistochemistry we characterized the neurotransmitter and hormonal phenotype of cells expressing GALR2 mRNA in the hypothalamus and pituitary gland. Our findings suggest GALR2 is a receptor mediating important functions of galanin in the hypothalamic-pituitary axis and may also play a role in hippocampal and cerebellar function.

Structural organization and chromosomal localization of three human galanin receptor genes

Human galanin receptor subtypes GALR1, GALR2, and GALR3 are encoded by separate genes that are located on human chromosomes 18q23, 17q25.3, and 22q13.1, respectively. The exon:intron organization of the gene encoding GALR2 (GALNR2) and GALR3 (GALNR3) is conserved, with exon 1 encoding the NH2-terminus to the end of transmembrane domain 3 and exon 2 encoding the remainder of the receptor, from the second intracellular loop to the COOH-terminus. This conservation of structural organization is indicative of a common evolutionary origin for GALNR2 and GALNR3. The exon:intron organization of the gene encoding GALR1 (GALNR1) is different from that of GALNR2 and GALNR3, with exon 1 encoding the NH2-terminus to the end of transmembrane domain 5, exon 2 encoding the third intracellular loop, and exon 3 encoding the remainder of the receptor, from transmembrane domain 6 to the COOH-terminus. The structural organization of GALNR1 suggests convergent evolution for this gene and represents a structural organization that is unique among genes encoding G-protein-coupled receptors.

Interactions between metals and microbial communities in New Bedford Harbor, Massachusetts

The fate of toxic metals in marine sediments depends on a combination of the physical, chemical, and biologic conditions encountered in any given environment. These conditions may vary dramatically, both spatially and temporally, in response to factors ranging from seasonal changes and storm events to human activities such as dredging or remediation efforts. This paper describes a program designed to evaluate the interrelationships between the microbial community and pollutants in the New Bedford Harbor, Massachusetts, area, a U.S. Environmental Protection Agency designated Superfund site. Research has focused on establishing distributional relationships between contaminant metals, fluxes of metals between sediments and the overlying water, changes in microbial diversity in response to metals, and potential use of the microbial community as a biomarker of contaminant availability. This research has shown that a significant flux of metals to the water column is mediated by benthic biologic activity, and that microbial communities may be a responsive marker of contaminant stress. A combination of biogeochemical studies and the use of molecular tools can be used to improve our understanding of the fate and effect of heavy metals released to aquatic systems.

Ligament force and joint motion in the intact ankle: a cadaveric study

The aims of this study were to measure the forces in the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) and the motion in the tibiotalar and subtalar joints during simulated weight-bearing in eight cadaver ankle specimens. An MTS test machine was used to apply compressive loads to specimens held in a specially designed testing apparatus in which the ankle position (dorsiflexion-plantarflexion and supination-pronation) could be varied in a controlled manner. The forces in the ATFL and CFL were measured with buckle transducers. Tibiotalar motion and total ankle joint motion were measured with an instrumented spatial linkage. The specimens were positioned sequentially at 10 degrees dorsiflexion, neutral, and 10 degrees and 20 degrees plantarflexion, and this sequence was repeated at 15 degrees supination, neutral pronation/supination, and 15 degrees pronation. Force and motion measurements were recorded in each of these positions with and without a 375 N compressive load simulating weight-bearing. From 10 degrees dorsiflexion to 20 degrees plantarflexion, all motion occurred in the tibiotalar joint. In contrast, the ratio of subtalar motion to tibiotalar motion was 3:1 for supination-pronation and 4:1 for internal-external rotation. Inverse loading patterns were observed for the ATFL and CFL from plantarflexion to dorsiflexion. Compressive loading did not affect CFL tension, but it magnified the pattern of increasing ATFL tension with plantarflexion. The largest increase in ATFL force was observed in supination and plantarflexion with a compressive load (76 +/- 23 N), whereas CFL tension mainly increased in supination and dorsiflexion with a compressive load (109 +/- 28 N). In conclusion, the results showed that the ATFL acted as a primary restraint in inversion, where injuries typically occur (combined plantarflexion, supination and internal rotation). Also, the subtalar joint was of primary importance for normal supination-pronation and internal-external rotation.

Amplification, expression, and steroid regulation of the preprogalanin gene in human breast cancer

The GALN gene encodes the preprogalanin protein that is cleaved to liberate the galanin peptide, a neuropeptide and tumor cell mitogen, and the galanin message-associated peptide, which is of unknown function. GALN is located at chromosome 11q13, a frequently amplified locus in diverse tumor types including breast cancer. To determine whether GALN may contribute to the tumor phenotype resulting from 11q13 amplification, we examined GALN amplification and preprogalanin mRNA levels in breast tumors and cell lines. GALN was amplified in a subset of breast tumors and cell lines that carried 11q13 amplifications. Preprogalanin mRNA was expressed in the majority of breast cancer cell lines, but Northern analysis failed to demonstrate a relationship between GALN amplification and preprogalanin mRNA levels. Eight of eight estrogen receptor-positive cell lines expressed detectable preprogalanin mRNA, and further investigation showed that preprogalanin mRNA was increased by treatment with estradiol and progestin and decreased by the removal of serum or treatment with antiestrogens. Thus, GALN amplification is unlikely to contribute to the phenotype conferred by 11q13 amplification in breast cancer, but preprogalanin mRNA is expressed by breast cancer cells and is under steroid hormone control in estrogen receptor-positive cells, opening the wider question of the role of this steroid-regulated neuropeptide in the normal and cancerous breast.

Structural organization of the mouse and human GALR1 galanin receptor genes (Galnr and GALNR) and chromosomal localization of the mouse gene

The neuropeptide galanin elicits a range of biological effects by interaction with specific G-protein-coupled receptors. Human and rat GALR1 galanin receptor cDNA clones have previously been isolated using expression cloning. We have used the human GALR1 cDNA in hybridization screening to isolate the gene encoding GALR1 in both human (GALNR) and mouse (Galnr). The gene spans approximately 15-20 kb in both species; its structural organization is conserved and is unique among G-protein-coupled receptors. The coding sequence is contained on three exons, with exon 1 encoding the N-terminal end of the receptor and the first five transmembrane domains. Exon 2 encodes the third intracellular loop, while exon 3 encodes the remainder of the receptor, from transmembrane domain 6 to the C-terminus of the receptor protein. The mouse and human GALR1 receptor proteins are 348 and 349 amino acids long, respectively, and display 93% identity at the amino acid level. The mouse Galnr gene has been localized to Chromosome 18E4, homoeologous with the previously reported localization of the human GALNR gene to 18q23 in the same syntenic group as the genes encoding nuclear factor of activated T-cells, cytoplasmic 1, and myelin basic protein.

Mechanics of the anterior drawer and talar tilt tests. A cadaveric study of lateral ligament injuries of the ankle

We analyzed the changes in lateral ligament forces during anterior drawer and talar tilt testing and examined ankle joint motion during testing, following an isolated lesion of the anterior talofibular ligament (ATFL) or a combined lesion of the ATFL and calcaneofibular ligament (CFL). 8 cadaver specimens were held in a specially designed testing apparatus in which the ankle position (dorsiflexion-plantarflexion and supination-pronation) could be varied in a controlled manner. Ligament forces were measured with buckle transducers, and joint motion was measured with an instrumented spatial linkage. An anterior drawer test was performed using an 80 N anterior translating force, and a talar tilt test was performed using a 5.7 Nm supination torque with intact ligaments, after sectioning of the ATFL, and again after sectioning of the CFL. The tests were repeated at 10 degrees dorsiflexion, neutral, and 10 degrees and 20 degrees plantarflexion. In the intact ankle, the largest increases in ATFL force were observed during testing in plantarflexion, whereas the largest increases in CFL force were observed in dorsiflexion. Isolated ATFL injury caused only small laxity changes, but a pronounced increase in laxity was observed after a combined CFL and ATFL injury.

Biomechanics of ankle ligament reconstruction. An in vitro comparison of the Broström repair, Watson-Jones reconstruction, and a new anatomic reconstruction technique

We wanted to use biomechanical testing in a cadaveric model to compare the Broström repair, the Watson-Jones reconstruction, and a new anatomic reconstruction method. Eight specimens were held in a specially designed testing apparatus in which the ankle position (dorsiflexion-plantar flexion and supination-pronation) could be varied in a controlled manner. Testing was done with intact ligaments and was repeated after sectioning of the anterior talofibular ligament and the calcaneofibular ligament and after a Broström repair, a Watson-Jones reconstruction, and a new anatomic reconstruction were performed. An anterior drawer test was performed using an anterior translating force of 10 to 50 N, and a talar tilt test was performed using a supination torque of 1.1 to 3.4 N-m. The forces in the anterior talofibular ligament and calcaneofibular ligament were measured with buckle transducers, and tibiotalar motion and total ankle joint motion were measured with an instrumented spatial linkage. The increase in ankle joint laxity observed after sectioning of both the anterior talofibular and calcaneofibular ligaments was significantly reduced by the three reconstructive techniques, although not always to the level of the intact ankle. Joint motion was restricted after the Watson-Jones procedure compared with that in the intact ankle. Unlike the Watson-Jones procedure, the ligament or graft force patterns observed during loading after the Broström repair and the new anatomic technique resembled those observed in the intact ankle.

Overlapping gene structure of the human neuropeptide Y receptor subtypes Y1 and Y5 suggests coordinate transcriptional regulation

The human y1 and y5 receptor genes are transcribed in opposite directions from a common promoter region on chromosome 4q31-q32. One of the alternately spliced 5' exons of the y1 receptor gene (1C) is also an integral part of the coding region of a novel neuropeptide Y receptor, Y5. Exon 1C of the y1 receptor gene, if translated from the opposite strand, encodes sequences corresponding to the large third intracellular loop of the Y5 receptor. The close proximity of the two neuropeptide Y receptor genes suggests that they have evolved from a gene duplication event with the small intron interrupting the coding sequence of the y1 gene being converted into a functional sequence within the y5 gene, while the reverse complementary sequence was utilized as an alternatively spliced 5' exon for the y1 gene. The transcription of both genes from opposite strands of the same DNA sequence suggests that transcriptional activation of one will have an effect on the regulation of gene expression of the other. As both Y1 and Y5 receptors are thought to play an important role in the regulation of food intake, coordinate expression of their specific genes may be important in the modulation of NPY activity.

Activity of centrally truncated analogues of neuropeptide Y at Y1 and Y2 receptor subtypes in vivo

Neuropeptide Y (NPY), a sympathetic cotransmitter, has both prejunctional and postjunctional actions in the cardiovascular system. In anaesthetized rats, the bioassay system used here, NPY attenuates cardiac vagal action (a prejunctional or Y2 action) and increases blood pressure (a postjunctional or Y1 action). Several NPY analogues were tested against NPY. In these, centrally located amino acid sequences of various lengths were removed, and replaced with simpler 'spacers'. As the parent NPY molecule is considered to exist in a U-shape, these central truncations were intended to shorten the depth of the U, while maintaining the integrity of its two ends. The centrally truncated NPY analogues examined here retain activity at both receptor subtypes in vivo. These findings indicate that the U-shape of the parent molecule probably exists to assist stability, but that receptor binding occurs through sequences closer to the termini.

Molecular cloning and characterisation of the mouse preprogalanin gene

Using a probe obtained by PCR amplification from mouse genomic DNA, a genomic clone was isolated covering the entire mouse preprogalanin gene. The mouse gene has an exon:intron organisation very similar to that of the rat and human genes. The first exon is noncoding while exons 2-5 carry the coding region. Exon 6 also encodes the stop codon and a polyadenylation signal. The deduced amino-acid sequence of mouse preprogalanin is 94% and 68% identical to the rat and human peptide, respectively. The amino-acid sequence of mouse galanin was confirmed by RT-PCR amplification of mouse brain RNA. The cloning of the mouse galanin gene should allow elucidation of the regulatory characteristics of its promoter and facilitate transgenic approaches to the analysis of galanin gene function in this species.

Characterization of the human brain putative A2B adenosine receptor expressed in Chinese hamster ovary (CHO.A2B4) cells

1. An [3H]-adenine pre-labelling methodology was employed to assay cyclic AMP generation by adenosine analogues in Chinese hamster ovary (CHO.A2B4) cells, transfected with cDNA which has been proposed to code for the human brain A2B adenosine receptor, and in guinea-pig cerebral cortical slices. 2. Adenosine analogues showing the following rank order of potency in the CHO.A2B4 cells (pD2 value): 5'-N-ethylcarboxamidoadenosine (NECA, 5.91) > adenosine (5.69) > 2-chloroadenosine (5.27) > N6-(2-(4-aminophenyl)-ethylamino)adenosine (APNEA, 4.06). The purportedly A2A-selective agonist, CGS 21680, failed to elicit a significant stimulation of cyclic AMP generation at concentrations up to 10 microM in CHO.A2B4 cells. In the guinea-pig cerebral cortex, NECA was more potent than APNEA with pD2 values of 5.91 and 4.60, respectively. 3. Of these agents, NECA was observed to exhibit the greatest intrinsic activity in CHO.A2B4 cells (ca. 10 fold stimulation of cyclic AMP), while, in comparison, maximal responses to adenosine (32% NECA response), 2-chloroadenosine (61%), and APNEA (73%) were reduced. 4. Antagonists of NECA-evoked cyclic AMP generation showed the rank order of apparent affinity (apparent pA2 value in CHO.A2B4 cells: guinea-pig cerebral cortex): XAC (7.89: 7.46) > CGS 15943 (7.75: 7.33) > DPCPX (7.16: 6.91) > PD 115,199 (6.95: 6.39) > 8FB-PTP (6.52: 6.55) > 3-propylxanthine (4.63: 4.59). 5. We conclude that, using the agents tested, the A2B adenosine receptor cloned from human brain expressed in Chinese hamster ovary cells exhibits an identical pharmacological profile to native A2B receptors in guinea-pig brain.

Intron 17 of the human retinoblastoma susceptibility gene encodes an actively transcribed G protein-coupled receptor gene

The human retinoblastoma susceptibility gene, a member of the tumor suppressor gene family, is located on chromosome 13q14.12-13q14.2 and consists of 27 exons that are distributed over 180 kb. This study shows that intron 17, the largest in size, consisting of nearly 72,000 bp, contains an open reading frame encoding a novel G protein-coupled receptor in the reverse orientation relative to the transcription of the retino-blastoma susceptibility gene. Correction of a frameshift mutation revealed that this novel G protein-coupled receptor is the human homolog of a chicken T-cell-specific receptor cDNA. This is an additional description of an actively transcribed protein-encoding gene positioned within an intron of another gene, suggesting that introns can have important structural functions.

Expression of the neuropeptide Y Y1 receptor in human embryonic kidney 293 cells: ligand binding characteristics, in situ hybridization and receptor autoradiography

The human neuropeptide Y Y1 receptor cDNA was transfected into human embryonic kidney 293 (HEK 293) cells and used to determine the selectivity of newly developed Y1 and Y2 radioligands in a model which expresses a single NPY receptor subtype. The Y1 receptor probe, [125I][Leu31,Pro34]PYY, binds with high afinity (KD of 0.4-0.6 nM) to Y1-transfected HEK 293 cells whereas the Y2 radioligand, [125I]PPY3-36 failed to demonstrate any significant labelling. Only non-selective (PYY) or selective Y1 receptor agonists behaved as potent competitors for [125I][Leu31,Pro34]PYY binding in transfected cells. Additionally, the efficacy of the transfection method used was evaluated at both the transcriptional and translational levels. In situ hybridization revealed the heterogeneous distribution of the NPY Y1 receptor mRNA expressed in transfected HEK 293 cells. Similarly, the levels of NPY Y1 binding sites per transfected cell varied as shown using [125I][Leu31,Pro34]PYY receptor autoradiography. Taken together, these results demonstrate that HEK 293 cells transfected with the NPY Y1 receptor cDNA expressed both the related receptor mRNA and protein albeit at different levels depending upon each transfected cell. Additionally, these data further establish the selectivity of the newly developed Y1 and Y2 radioligands.

Multiple promoters regulate tissue-specific expression of the human NPY-Y1 receptor gene

Several cDNA clones encoding the human neuropeptide Y-Y1 receptor have been isolated that contain differing sequences at their 5'-ends. The divergence occurs at a splice junction in the 5'-untranslated region, suggesting that at least three forms of the neuropeptide Y-Y1 receptor transcript are generated by alternative splicing at this site. Genomic clones have been isolated that encompass the alternatively spliced 5'-exons. The exons are found 6.4, 18.4, and 23.9 kilobases upstream of exon 2. In the corresponding promoter regions of the various exons, possible response elements for the glucocorticoid receptor, as well as potential binding sites for the AP-1, AP-2, and NF-kappa B transcription factors are found. Analysis of NPY-Y1 transcripts in various cell types demonstrates the tissue-specific activation of the three promoters.

Synergistic interaction of Y1-neuropeptide Y and alpha 1b-adrenergic receptors in the regulation of phospholipase C, protein kinase C, and arachidonic acid production

Neuropeptide Y (NPY) and norepinephrine, found colocalized in sympathetic neurons innervating blood vessels, exert synergistic responses on vasoconstriction. To examine the signaling mechanisms involved, free of complications associated with mixed receptor populations, we have established a stable Chinese hamster ovary cell line expressing both Y1-NPY and alpha 1b-adrenergic receptors. Occupation of either receptor species, with 100 nM peptide YY (PYY) or 10 microM phenylephrine (PE), respectively, resulted in a rapid increase in the cytoplasmic free calcium concentration ([Ca2+]i) as assessed with Fura-2/AM. The rise due to PYY, but not that due to PE, was abolished by pretreatment with pertussis toxin. Both responses were largely maintained in the absence of extracellular Ca2+, but abolished by prior depletion of intracellular Ca2+ pools with either thapsigargin or 2,5-di-(t-butyl)-1,4-benzohydroquinone. Using cells prelabeled with myo-[3H]inositol, PE promoted a rapid (5 s) rise in inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) as analyzed by anion-exchange high pressure liquid chromatography, whereas the response to PYY (first significant at > 15 s post-stimulation) was too slow to play a causative role in Ca2+ mobilization. Combination of PE and PYY resulted in increases in [Ca2+]i which were at best additive, whereas they promoted a clearly synergistic rise in Ins(1,4,5)P3 at both 15 and 60 s. Co-stimulation also resulted in a synergistic activation of both protein kinase C (PKC) and [3H]arachidonic acid release. In either instance PYY alone was without effect. The potentiation of arachidonic acid release was abolished by depletion of cellular PKC following chronic treatment with phorbol esters. It is suggested that the ability of PYY to mobilize Ca2+ in an Ins(1,4,5)P3-independent fashion minimizes the functional importance of the capacity to potentiate PE-stimulated Ins(1,4,5)P3 generation. Instead the major consequences of the synergistic activation of phospholipase C are mediated via PKC, the other route of the signaling pathway.

Characterization of the 5'-flanking region of the human preprogalanin gene

Expression of the human galanin gene was analysed using a 3.5-kb DNA fragment comprising the 5'-flanking sequence of the gene. This sequence contains a TATA box (ATATATA) preceded by numerous potential binding sites for transcription factors such as SP1, AP2, and NF kappa B. Three half-palindromic estrogen response elements (EREs, GGTCA) are also found at positions -1,162, -361, and -122 bp relative to the transcription start site. To localize functionally important portions of the promoter region, several shorter fragments of the galanin 5'-flanking region were placed upstream from the chloramphenicol acetyltransferase (CAT) reporter gene. In transient transfection assays, all constructs demonstrated substantial transcriptional activity in both rat glioma/mouse neuroblastoma hybrid cells (NG108-15) and Chinese hamster ovary (CHO-K1) cells. Comparison of the basal expression levels of the different constructs suggests the presence of a negative modulator between positions -1,891 and -207. When cotransfected into NG108-15 cells with the human estrogen receptor cDNA, estrogen did not induce transcription of the human galanin gene at physiological levels of estrogen receptor, although transcription was induced up to 30-fold in the presence of high levels of receptor.

Gene duplication of the human peptide YY gene (PYY) generated the pancreatic polypeptide gene (PPY) on chromosome 17q21.1

Neuropeptide Y (NPY), peptide YY (PYY), and pancreatic polypeptide (PP) are structurally related but functionally diverse peptides, encoded by separate genes and expressed in different tissues. Although the human NPY gene has been mapped to chromosome 7, we demonstrate here that the genes for human PYY and PP (PPY) are localized only 10 kb apart from each other on chromosome 17q21.1. The high degree of homology between the members of this gene family, both in primary sequence and exon/intron structure, suggests that the NPY and the PYY genes arose from an initial gene duplication event, with a subsequent tandem duplication of the PYY gene being responsible for duplication of the PYY gene being responsible for the creation of the PPY gene. A second weaker hybridization signal also found on chromosome 17q11 and results obtained by Southern blot analysis suggest that the entire PYY-PPY region has undergone a further duplication event.

Seminalplasmin: recent evolution of another member of the neuropeptide Y gene family

Seminalplasmin, the major basic protein of bull semen, an important regulator of calcium transport in bovine sperm and a positive modulator of the zona pellucida-induced acrosome reaction, is shown to be a recently created member of the neuropeptide Y gene family. Sequence analysis of the bovine peptide YY-pancreatic polypeptide gene cluster reveals an unexpected and extensive homology between seminalplasmin and the neuropeptide Y gene family, at the level of both gene structure and primary amino acid and nucleotide sequences. The extremely high degree of homology to the peptide YY gene, in both coding and especially noncoding regions, suggests that the seminalplasmin gene has arisen by a very recent gene duplication of the bovine peptide YY gene. Despite the more than 95% nucleotide sequence identity, a few specific mutations in the seminalplasmin gene have resulted in both the loss of the amino- and carboxyl-terminal cleavage sites characteristic of all other members of the neuropeptide Y family and the acquisition of a function apparently unrelated to the neurotransmitter/endocrine role of peptide YY.

Human neuropeptide Y1 receptor expressed in Escherichia coli retains its pharmacological properties

The coding region of the gene for the human neuropeptide Y (NPY) Y1 receptor was fused to the maltose binding protein gene. Expression of this transcription unit, after derepression with isopropyl beta-D-thiogalactopyranoside, was evidenced by the appearance of a protein of higher molecular weight, as well as the native maltose binding protein, both of which were immunoreactive with anti-maltose binding protein antibodies. Specific [125I]NPY binding activity was found associated mainly with the inner bacterial membrane fraction, suggesting that the receptor is correctly folded in this membrane. Competition binding experiments using NPY Y1- and Y2-specific ligands clearly exhibited a NPY Y1 specific pharmacological profile with Kd values indistinguishable from those of the native receptor. These results suggest that the membrane environment required by the human NPY Y1 receptor for specific high-affinity ligand binding is conserved in this heterologous bacterial system and can be used for detailed analyses of ligand-receptor interaction and drug screening.

Neuropeptide Y and regulation of the cardiovascular system

CONTROL OF CARDIOVASCULAR SYSTEM: Neuropeptide Y has three major activities which are important in the modulation of blood pressure homeostasis. When released from sympathetic neurons innervating the cardiovascular system, this peptide causes direct long-lasting vasoconstriction, inhibits the release of noradrenaline and other neurotransmitters and potentiates the action of noradrenaline and other pressor agents.

RECEPTOR SUBTYPE DIVERSITY

At least two major subtypes of neuropeptide Y receptor have been defined by pharmacological criteria, and the major subtype involved in the control of blood pressure (Y1) has been isolated by molecular cloning. Analysis of the cloned DNA sequence has confirmed that the receptor is a member of the G protein-coupled receptor superfamily and when expressed in various cell lines can couple to both the inhibition of adenylate cyclase and the elevation of intracellular calcium. NEUROPEPTIDE Y ANTAGONISTS: A specific neuropeptide Y antagonist has been developed which significantly lowers the dose-dependent neuropeptide Y-induced pressor response in normal rats. The inhibition is specific for the peptide and also selective for the postsynaptic Y1 receptor-mediated vasoconstrictor activity. Administration of this specific and selective inhibitor significantly reduces resting arterial blood pressure, which remains depressed for up to 4 h in normal and spontaneously hypertensive rats.

CONCLUSIONS

Inhibition of endogenous neuropeptide Y activity demonstrates that this peptide makes a significant contribution to the control of blood pressure and indicates the therapeutic potential of neuropeptide Y inhibitors as a new class of antihypertensive agent. The molecular cloning of the neuropeptide Y receptor subtype responsible for both the direct vasoconstrictor activity of the peptide and the potentiation of the action of other pressor agents represents an important advance in our understanding of the molecular basis of neuropeptide Y action and will help in the development of selective neuropeptide Y antagonists.

Isolation and chromosomal localization of a novel human G-protein-coupled receptor (GPR3) expressed predominantly in the central nervous system

Degenerate oligonucleotide primers designed against known G-protein-coupled receptors were used in polymerase chain reaction amplification to isolate a novel receptor sequence (R4) from a rat insulinoma cell line and its human homolog (GPR3) from a human neuroblastoma cDNA library. The novel human receptor sequence is expressed in low abundance predominantly in the central nervous system and at low levels in the lung and kidney. The gene encoding GPR3 is intronless within the coding region, contains at least one intron in the 5'-untranslated region, and has been localized to chromosome 1p34.3. The activating ligand for the homologous receptors R4 and GPR3 is not known, but sequence similarity with the closely related orphan rat receptor R334 [FEBS Lett. 292:243 (1991)] suggests that R334 and the homologous receptors R4 and GPR3 probably represent two discrete molecular subtypes that interact with the same or closely related ligands.

Exclusion of close linkage of bipolar disorder to the Gs-alpha subunit gene in nine Australian pedigrees

Growing evidence suggests that guanine nucleotide binding proteins (G proteins) may be involved in both the pathogenesis and treatment of bipolar affective disorder. Both overactive G proteins and increased levels of the alpha subunit of the stimulatory form (Gs-alpha) have been demonstrated in peripheral leucocytes of manic patients while an increase of Gs-alpha subunit levels has also been found in a postmortem study of bipolar disorder. The function of Gs and Gi alpha subunits has now been shown to be affected by lithium. The present study aimed to determine whether bipolar affective disorder was linked to the Gs-alpha subunit gene which has been mapped to chromosomal region 20q13.2. Linkage analysis utilized the PCR amplification of a portion of the Gs-alpha gene that contains a dinucleotide repeat (CA repeat) polymorphism. Linkage of bipolar disorder and recurrent depression to the Gs-alpha subunit gene was tested using a series of autosomal dominant and recessive models with varying penetrance levels. Additionally, linkage was examined using a series of levels of definitions of affective illness. Close linkage to the Gs-alpha subunit gene was strongly excluded using each model and definition. Thus, our study indicates that a genetic defect in the Gs-alpha subunit gene is unlikely to be the cause of bipolar disorder.

A novel neuropeptide Y analog, N-acetyl [Leu28,Leu31]neuropeptide Y-(24-36), with functional specificity for the presynaptic (Y2) receptor

We have carried out functional and in vitro studies on a novel analog of neuropeptide Y which shows selectivity for the prejunctional or neuropeptide Y Y2 receptor. In anaesthetised rats N-acetyl [Leu28,Leu31]neuropeptide Y-(24-36) attenuates cardiac vagal action (a prejunctional or neuropeptide Y Y2 action) and has no significant pressor effects (postjunctional or neuropeptide Y Y1 action). In the human neuroblastoma cell line (SMS-KAN) which expresses and endogenous Y2-like neuropeptide Y receptor, N-acetyl [Leu28,Leu31]neuropeptide Y-(24-36) competes with peptide YY for binding sites with an IC50 of 0.5 +/- 0.1 nM. In contrast in a fibroblast Chinese hamster ovary cell line which expresses the cloned human neuropeptide Y Y1 receptor and is used to study changes in cytosolic calcium evoked by (a neuropeptide Y Y1 effect), N-acetyl [Leu28,Leu31]neuropeptide Y-(24-36) showed no activity even at high concentrations. The steric structure for this novel compound has been determined using proton nuclear magnetic resonance (NMR) spectroscopy and it is consistent with the C-terminal end of published structures of neuropeptide Y. We suggest acetylation and amino acid substitutions stabilise the molecule and allow it to bind only to the neuropeptide Y Y2 receptor.

Genomic organization and localization of the gene encoding human preprogalanin

An approximately 35-kb region of genomic DNA encoding the human preprogalanin gene including 5' and 3' flanking sequences has been cloned and characterized. Exons and flanking introns were sequenced to determine the structural organization of the gene. The gene spans 6.5 kb, with the first exon encoding only the 5' untranslated sequence. The coding region of preprogalanin and the 3' untranslated sequence is divided into five exons. Using high-resolution fluorescence in situ hybridization, the position of the single human preprogalanin gene was localized to chromosome 11q13.3-q13.5. Several oncogenes have been mapped to this region, which is also the breakpoint for the translocation t(11;14)(q13;q32) in chronic lymphocytic leukemia and diffuse B-cell lymphoma.

Neuropeptide-Y Y1 receptor gene polymorphism: cross-sectional analyses in essential hypertension and obesity

Neuropeptide Y increases blood pressure and appetite, disorders of which have a genetic component. The present study examined the neuropeptide-Y Y1 receptor gene (NPYY1R) for involvement in essential hypertension (HT) and obesity. Frequency of alleles of the only known variant, involving a point mutation in intron 1, was determined by PCR and PstI digestion. Minor allele frequency was 0.37 in 75 HT offspring of two HT parents, compared with 0.35 in 86 normotensives (NTs) ( chi 2 = 0.11; P = 0.73). In obese and lean HTs frequency was 0.40 and 0.35 (chi 2 = 0.51; P = 0.46); and was 0.38 and 0.34 in obese and lean NTs (chi 2 = 0.16; P = 0.69). In conclusion, variant(s) in linkage disequilibrium with the NPYY1R RFLP are not involved in HT or obesity.

Potent effects of human galanin in man: growth hormone secretion and vagal blockade

Human galanin (hGAL) is a 30-amino acid neurohormone that has recently been shown to differ significantly from porcine and rat GAL. We investigated the endocrine and cardiovascular effects of hGAL in eight male volunteers. On three separate occasions, each received a 90-min infusion of saline, low dose (33 pmol/kg.min) and high (132 pmol/kg.min) dose hGAL, combined with an iv glucose bolus (to assess effects on insulin and GH release). hGAL was undetectable, 1.4 +/- 0.2 nmol/L, and 3.7 +/- 0.5 nmol/L during control, low dose, and high dose studies, respectively. The half-life of hGAL was 3.5 +/- 0.5 min. GH levels rose significantly in both studies (vs. control) and were not suppressed by hyperglycemia [low dose area under the curve (AUC), 1827 +/- 348 micrograms/min.L (P < 0.05); peak, 19.5 +/- 5.3 micrograms/L; high dose AUC, 1896 +/- 401 micrograms/min.L (P < 0.005); peak, 28.0 +/- 7.5 micrograms/L]. PRL levels rose significantly with the high dose study only (AUC, 12.8 +/- 1.1 micrograms/min.L; P < 0.01). FSH, LH, and catecholamine levels were unchanged. Glucose-stimulated insulin release was not inhibited. There was a dose-dependent increase in pulse rate and a profound decrease in sinus arrhythmia, but no change in blood pressure. These cardiovascular effects have not been reported with studies in humans using GAL of other species. We conclude that hGAL may play an important role in man in modulating GH secretion and cardiac vagal tone, but not insulin release.

Molecular cloning, characterization, and localization of the human homolog to the reported bovine NPY Y3 receptor: lack of NPY binding and activation

A cDNA clone encoding the human homolog of the bovine cDNA clone LCR1 was isolated from a human lung cDNA library. The 1,670-bp-long nucleotide sequence predicts a single open reading frame of 352 amino acids, with a 92% amino acid identity to a bovine sequence reported to represent the neuropeptide Y (NPY) Y3 receptor. The amino acid sequence shares features common to many other G-protein-coupled receptors, including the seven transmembrane regions and putative glycosylation and phosphorylation sites. Polymerase chain reaction (PCR) analysis of human-hamster hybrid cell DNA reveals that the corresponding gene is located on human chromosome 2. Although the ligand for the bovine receptor has previously been identified as NPY in binding studies, extensive analysis with the human homolog transfected in several different cell lines failed to confirm this classification. Furthermore, the receptor shows 36% identity to both the human interleukin-8 (IL-8) and angiotensin II receptors but only 21% identity to the human NPY Y1 receptor. In addition, NPY and a number of other ligands fail to induce any change in cytosolic calcium levels in transfected cells, suggesting that this clone represents a novel neuropeptide receptor.

Exclusion of close linkage of bipolar disorder to the dopamine D3 receptor gene in nine Australian pedigrees

The recently cloned dopamine D3 receptor (DRD3) gene is of potential relevance to the aetiology of bipolar disorder because of an almost exclusive expression in limbic tissue, the region of the brain putatively responsible for control of emotion. We therefore aimed to determine whether bipolar disorder in nine pedigrees (with 171 members) was linked to this receptor gene, which has been mapped to chromosomal region 3q 13.3. Linkage of bipolar disorder and recurrent depression to the DRD3 gene was tested using a series of autosomal dominant and recessive models with varying penetrance levels. Additionally, linkage was examined using a series of levels of definitions of affective illness (ranging from bipolar I alone to all affective disorders). Close linkage to the DRD3 gene was strongly excluded using each model and definition, and these conclusions persisted when a wide range of rates of 'sporadic' (non-genetic) presentations of illness were incorporated in the analysis.