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Biomedical subjects

D A Walsh

Publications and source records attributed to D A Walsh.

At least 55 records · Page 3Linked to original sources
PubMed1997

Fractionated-dose effect of X-irradiation on the induction of neural tube defects in mice.

This experiment examined whether mouse embryos have a radio-adaptive response to the induction of malformations. Pregnant Slc:ICR mice were exposed to 0.05 Gy X-radiation followed by 0.5 or 1.0 Gy 4 hr later on day 8 of pregnancy. To compare this with the effect of single doses, four other groups were exposed to 0.5, 0.55, 1.0 or 1.05 Gy. All dams were put to death on day 18, and fetuses were examined for malformations. The frequency of neural tube defects induced by the fractionated irradiation into 0.05 Gy and 1.0 Gy was significantly higher than that induced by single doses of 1.0 and 1.05 Gy. Among groups exposed to a dose split into 0.05 and 0.5 Gy, and single doses of 0.5 and 0.55 Gy, there was no significant difference in incidence of the malformation. The present findings suggest that mouse embryos are not adapted to X-irradiation, but become more susceptible following a low-dose exposure.

Abnormalities, Radiation-Induced↗
PubMed1997

Hyperthermia, teratogenesis and the heat shock response in mammalian embryos in culture.

Hyperthermia is a recognized teratogen in animals and there is strong evidence that it also causes significant damage to human embryos. Studies with induced hyperthermia in pregnant animals defined the defects which are produced, the susceptible stages of development, and threshold doses of heat required to cause defects. The in vivo experiments lacked precision because of variability of embryonic development at a given conceptual age, varying maternal responses to agents causing temperature elevations, the difficulty in measuring embryonic temperature and the possibility that defects were caused by toxic changes in maternal metabolism. These variables were eliminated by the use of postimplantation whole rat and mouse embryo cultures, which were exposed to various doses of heat at closely defined stages of development. The studies showed that heat acts directly on embryos and that elevations of 2 degrees C and greater sustained over early rat organogenesis cause defects mainly by causing apoptotic cell death especially in the developing central nervous system. A moderate, non damaging exposure is followed within 15 min by protection for up to 8 h against a more severe and otherwise teratogenic exposure. The protective heat shock response is accompanied by a reduction of normal protein synthesis and concurrent synthesis of heat shock proteins (HSP90, 71, 47, 27). Most HSP in these families are also present constitutively in embryos, probably having important roles in protecting newly synthesized proteins from aggregation and facilitating folding into their normal functional configurations. The appearance of induced HSP and hsp mRNA at known sites of thermal damage suggests a protective role. Heat induced cell death by apoptosis is a feature of teratogenic damage to the developing brain. Apoptosis could be a by-product of a damaging heat exposure because of a priority favoring induction of the heat shock response over the normal gene program for organogenesis, survival being achieved at the expense of normal development.

Animals↗
PubMed1996

Patterned expression in familial Klippel-Feil syndrome.

Klippel-Feil syndrome (KFS) is characterised by congenital fusion of vertebrae within the rostral spine. The first KFS gene (SGM1) locus identified on chromosome 8 segregates with vertebral fusions and associated vocal impairment within the KF2-01 family (Clarke et al., '94, '95). Here, we describe the unique pattern of variable phenotypic expression within the KF2-01 family. The pattern of anomalies revealed a cumulative, rostrocaudal graded sequence of skipped vertebral fusions. This fusion pattern presents striking similarities with the mutant phenotype and gene expression profile of the Drosophila segment polarity gene engrailed.

Adolescent↗
PubMed1996

Innervation and neurokinin receptors during angiogenesis in the rat sponge granuloma.

Angiogenesis is an essential component of wound healing and inflammation. In the rat subcutaneous sponge implantation model, angiogenesis can be enhanced by administration of the sensory neuropeptide, substance P. We have used quantitative in vitro receptor autoradiography and immunohistochemistry to investigate the development of endogenous neurovascular regulatory systems in the newly-formed granulation tissue of this model. The fraction of endothelial cells immunoreactive for proliferating cell nuclear antigen, endothelial fractional area, and 133Xe clearance were used as measures of endothelial proliferation, neovascularization, and blood flow, respectively. Endothelial proliferation occurred predominantly in tissues surrounding the sponge, and peaked before neovascularization of sponge stroma and the establishment of sponge blood flow. Substance P-containing sensory nerves and specific, high affinity substance P binding sites with characteristics of neurokinin receptors of the NK1 subclass, were localized to microvessels surrounding the sponge at all time points. Lower density substance P binding sites were localized to newly formed microvessels within the sponge stroma, progressively increasing in density from day 4 to day 14. Nerve fibres were observed in the stroma of only 2 of 6 sponges at day 14, and none at earlier time points. These data support the hypothesis that substance P-enhanced angiogenesis in this model results from a direct action on microvascular NK1 receptors. Neovascularization is a sequential process, with early endothelial proliferation followed by new vessel formation and increased blood flow, with maturation of endogenous neurovascular regulatory systems occurring late in this process in inflamed tissues.

Animals↗
PubMed1995

Heat-stable inhibitor protein derived peptide substrate analogs: phosphorylation by cAMP-dependent and cGMP-dependent protein kinases.

The phosphorylation of substrate peptides derived from PKI, the heat-stable inhibitor protein of the cAMP-dependent protein kinase (PKA), has been studied with both PKA and the cGMP-dependent protein kinase (PKG) using a variety of substitution and deletion analogs. On the basis of Km, kcat and kcat/Km values, (Ser21)PKI alpha(14-22) amide (numbering based upon native PKI alpha) is the most effective peptide substrate yet discovered for either kinase, although other peptides, while phosphorylated considerably less efficiently by PKG, are more specific. Although the inhibitory peptide corresponding to this sequence (i.e., with an Ala at position 21) is a much more potent inhibitor of PKA than of PKG (approximately 250-fold), PKG actually exhibits a 60% higher kcat than does PKA with the (Ser21)PKI alpha(14-22) amide substrate peptide, with only a 20-fold higher Km value. The two key PKI residues within this peptide which were found to be essential for substrate activity with both kinases were Arg18 (P-3) and Ile22 (P+1). The Arg19 (P-2) residue, which contributes significantly to both PKI-based peptide inhibitors and substrates of PKA, was only a more minor contributor to PKG substrate efficacy. Of particular note, the Phe10 (P-11) residue, which contributes very substantially to high affinity binding of both PKI and longer PKI peptide inhibitors, neither positively nor negatively affects the kinetics of either PKA or PKG with PKI-based substrates.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1995

Conformationally constrained analogs of protein kinase inhibitor (6-22)amide: effect of turn structures in the center of the peptide on inhibition of cAMP-dependent protein kinase.

The high-affinity interaction between protein kinase inhibitor (PKI)(6-22)amide(Thr6-Tyr-Ala-Asp-Phe-Ile-Ala-Ser-Gly-Arg-Thr-Gly- Arg-Arg-Asn- Ala-Ile22-NH2) and the catalytic subunit of cAMP-dependent protein kinase requires both the N-terminal Thr6 to Ile11 sequence of the inhibitor peptide and its C-terminal pseudosubstrate site comprised of Arg15 to Ile22. Small angle X-ray scattering data indicate that PKI(6-22)amide has a compact, rather than extended, structure in solution (Reed J et al., 1989, Biochem J 264:371-380). CD spectroscopic analysis of the PKI peptide led to the suggestion that a beta-turn structure might be located in the -Ala12-Ser-Gly-Arg15-connecting sequence in the middle of the molecule (Reed J, Kinzel V, Cheng HC, Walsh DA, 1987, Biochemistry 26:7641-7647). To investigate this possibility further, conformationally constrained and flexible analogs of PKI(6-22)amide were synthesized and used to study the structure-function relationships of this central portion of the inhibitor. (Des12-14)PKI(6-22) amide exhibited over a 200-fold loss in inhibitory activity. Replacement of the omitted -Ala12-Ser-Gly14-sequence with aminocaprylic acid yielded an analog that regained more than 90% of the lost binding energy. The D-alanine14 PKI analog was as potent as the parent peptide, whereas the beta-alanine14 and the sarcosine14 analogs were only 10-fold less active. Several peptides that promoted a beta-turn structure at residues 12-15 showed about 200-fold decreases in inhibitory activity. Two constrained analogs that could not assume a beta-turn conformation were only 30-fold less potent than PKI(6-22)amide. Thus, the structure of the central connecting portion of the PKI peptide, encompassing residues 12-15, greatly influences its ability to effectively bind to and inhibit the catalytic subunit. We conclude, however, that a formal beta-turn at this position is not required and is actually detrimental for a high-affinity interaction of PKI(6-22)amide with the enzyme. These results are interpreted in light of the Fourier-transform infrared spectra of the peptide analogs and the crystal structure of the peptide bound at the active site of the protein kinase (Knighton DR et al., 1991b, Science 253:414-420).

Amino Acid Sequence↗
PubMed1995

Autoradiographic localization and characterization of [3H]alpha-trinositol (1D-myo-inositol 1,2,6-trisphosphate) binding sites in human and mammalian tissues.

alpha-Trinositol (1D-myo-inositol 1,2,6-trisphosphate, PP56) selectively and potently inhibits the vasoconstrictor effects of neuropeptide Y (NPY). The authors used quantitative in vitro receptor autoradiography to localize and characterize [3H]alpha-trinositol binding sites in human and mammalian tissues. [3H]alpha-trinositol bound specifically to vascular and nonvascular smooth muscle in human, porcine and rat tissues. Binding was time dependent, reversible, saturable and specific for alpha-trinositol compared with inositol 1,4,5-trisphosphate, inositol 1,3,4,5-tetrakisphosphate (Ins-1,3,4,5-P4) and inositol hexakisphosphate (Ins-P6). Binding to each structure gave Kd values of 5 to 20 nM and was consistent with a homogeneous population of sites. Binding was optimal at pH 5 and at low calcium concentrations. Comparison with [125I]Bolton Hunter-labeled NPY ([125I]BH-NPY) binding in porcine tissues revealed 1) a partial colocalization but Bmax values for [3H]alpha-trinositol binding some two orders of magnitude higher than for [125I]BH-NPY and 2) failure of each of the two ligands to inhibit binding of the other. Comparison of [3H]alpha-trinositol with [3H]Ins-1,3,4,5-P4 binding in human umbilical cord revealed that both ligands bound specifically to vascular smooth muscle but that only [3H]Ins-1,3,4,5-P4 bound to arterial endothelium. Both ligands bound to sites with rank orders of affinity Ins-1,3,4,5-P4 > Ins-P6 > inositol 1,4,5-trisphosphate. alpha-Trinositol had, however, three orders of magnitude higher affinity for [3H]alpha-trinositol than [3H]Ins-1,3,4,5-P4 binding sites; Ins-1,3,4,5-P4 and Ins-P6 had higher affinity for [3H]Ins-1,3,4,5-P4 binding sites. Specific [3H]alpha-trinositol binding sites may represent receptors by which alpha-trinositol inhibits NPY effects on vascular tone.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Multiple pathway signal transduction by the cAMP-dependent protein kinase.

Since its discovery a quarter century ago, the cAMP-dependent protein kinase has been a central model for study of the mode of transduction of second messenger signals; more than 300 protein kinases are now known to play keys roles in cellular control. Multiple cellular events are initiated by the activation of the cAMP-dependent protein kinase and correlated with these events has been the identification of a broad spectrum of protein substrates. From model substrates and inhibitors an excellent understanding has been obtained of the "optimum" sequence for protein phosphorylation by the cAMP-dependent protein kinases, and now, from pioneering crystal structure studies, we are beginning to understand exactly how an optimum substrate can interact with and be efficiently phosphorylated by the kinase. The next important step is for us to understand the full sequence of events that occurs within the cell upon activation of the protein kinase, and it is abundantly evident that this is indeed a complex process. It is not sufficient to simply know which proteins are phosphorylated but it is critical that we understand the dynamics of the events surrounding the phosphorylation of multiple proteins, what factors dictate those dynamics, and what might happen when the sequence of events is perturbed. This review focuses on the first simple question that must be addressed, namely, how might proteins vary as substrates for the cAMP-dependent protein kinase and what ramifications might such variations have for the consequential events within the cell?

Amino Acid Sequence↗
PubMed1994

AT1 receptor characteristics of angiotensin analogue binding in human synovium.

1. Angiotensin II (AII) reduces blood flow, modulates vascular remodelling and is a growth factor. Human inflammatory arthritides are characterized by synovial hypoperfusion, hypoxia and proliferation. We aimed to localize and characterize receptors for AII in human synovium. 2. We used quantitative in vitro receptor autoradiography with [125I]-(Sar1, Ile8)AII and [125I]-AII on human synovium from patients with chondromalacia patellae, osteoarthritis and rheumatoid arthritis. 3. [125I]-(Sar1, Ile8)AII and [125I]-AII bound to similar sites on synovial blood vessels, lining cells and stroma. Binding to microvessels (< 100 microns diameter) was more dense than to arteriolar media, and vascular binding was more dense than that to lining cells and stroma. 4. Microvessels and arterioles which displayed angiotensin converting enzyme-like immunoreactivity also displayed specific binding of [125I]-(Sar1, Ile8)AII. 5. Specific binding of [125I]-(Sar1, Ile8)AII to each structure was completely inhibited by 10 microM dithiothreitol and was inhibited by unlabelled ligands with the rank order of potency (Sar1, Ile8)AII > AII > losartan = SKF108566 > PD123319 indicating an AT1 subclass of angiotensin receptor. 6. GTP gamma S (1 microM) abolished specific binding of [125I]-AII and abolished the high affinity component of the binding inhibition curve for AII against [125I]-(Sar1, Ile8)AII, indicating G protein coupling. 7. The distribution of [125I]-(Sar1, Ile8)AII binding sites was similar in all disease groups and no significant differences in binding densities, affinities or specificities were observed between disease groups. 8. Locally generated AII may act on synovial AT1 receptors to modulate synovial perfusion and growth. Specific AT1 receptor antagonists should help elucidate the role of angiotensins in human arthritis.

Adult↗
PubMed1994

Differences in the distribution and characteristics of tachykinin NK1 binding sites between human and guinea pig lung.

1. The distribution and characteristics of tachykinin NK1 binding sites have been compared in human and guinea pig lung using quantitative in vitro receptor autoradiography with [125I]-Bolton Hunter-labelled substance P ([125I]-BH-SP). In addition, the effects on these sites of ovalbumin sensitization and challenge have been determined in guinea pig lung. 2. [125I]-BH-SP bound specifically and with high affinity to microvascular endothelium in both human and guinea pig lung, but to bronchial smooth muscle and pulmonary artery media in only guinea pig lung. 3. Specific binding of [125I]-BH-SP to guinea pig bronchial smooth muscle was positively correlated with airway diameter in the range 150-800 microns and was less dense in trachea than in main bronchi. 4. [125I]-BH-SP binding was inhibited by tachykinins with rank orders of affinity of SP > NKA > NKB (human microvessels) and SP > NKA = NKB (guinea pig bronchi and pulmonary arteries). NKA displayed a higher affinity for [125I]-BH-SP binding sites in human microvessels than in guinea pig tissues (P < 0.0001), indicating differences in selectivity for tachykinins between human and guinea pig NK1 receptors. 5. In both human and guinea pig lung, [125I]-BH-SP binding was inhibited by the specific tachykinin receptor antagonists FK888 (NK1 selective antagonist) and FK224 (mixed NK1/NK2 antagonist), with FK888 displaying equal affinity to SP and > 500 times higher affinity than FK224. SP, NKA, NKB and FK888 exhibited similar affinities for [125I]-BH-SP binding sites in both guinea pig arteries and bronchi. 6. Similar distributions, densities and characteristics of [I251]-BH-SP binding sites were demonstrated in oval bumin-sensitized and -challenged guinea-pig lung and in naive animals.7. Differences in the distribution and characteristics of NKI binding sites labelled with [125I]-BH-SP between guinea pig and human lung suggest limitations in the use of guinea pig models for studying roles of tachykinins in pulmonary disease. However, the similar microvascular distributions of NK,binding sites in human and guinea pig lung suggest that the selective tachykinin receptor antagonistsFK888 and FK224 may be useful in the management of airway inflammation in man.

Animals↗
PubMed1994

Effect of three animal models of inflammation on nerve fibres in the synovium.

OBJECTIVES: Both sensory and sympathetic nerve fibres are depleted in the synovium in rheumatoid arthritis (RA). The hypothesis that the induction of an inflammatory response in the synovium is capable of causing depletion of nerve fibres was tested. METHODS: To investigate this phenomenon experimental arthritis in the rat was induced by three different methods and the synovium was examined for evidence of nerve depletion by immunocytochemistry. RESULTS: In a synovitis induced by latex spheres, a mainly macrophage foreign body type reaction, no nerve depletion was seen. In contrast both in an antigen-induced and a hydrogen peroxide-induced model of arthritis nerve fibre depletion was observed. This appeared to affect sensory and sympathetic nerve fibres equally. Nerve fibre depletion was only seen in areas of inflammatory cell infiltration indicating that a mixed lymphocyte and macrophage population of cells may be necessary for this effect. CONCLUSIONS: An inflammatory response, containing lymphocytes and macrophages, in the synovium is capable of the depletion of the finely myelinated and unmyelinated neuropeptide-containing nerves.

Animals↗
PubMed1994

Substance P in intervertebral discs. Binding sites on vascular endothelium of the human annulus fibrosus.

The annulus fibrosus of the human intervertebral disc is sparsely innervated, some of the fibers containing substance P. We could demonstrate, by autoradiography, binding sites for substance P localized on the endothelium of small blood vessels in the annulus fibrosus of human intervertebral discs removed during anterior fusion for back pain. In binding inhibition studies, binding of 125I-Bolton Hunter-substance P was inhibited by unlabeled substance P and the related tachykinins neurokinin A and neurokinin B with a rank order of potency substance P > NKA > NKB. Specific binding was reduced > 75 percent by 5'-guanylylimidodiphosphate, indicating G-protein coupling. These features are characteristic of an NK1 receptor through which vascular effects, i.e., vasodilation, plasma extravasation and angiogenesis of substance P, are mediated. The presence of NK1 receptors on blood vessels in the annulus fibrosus may indicate a role for substance P in tissue repair although acute proinflammatory effects may contribute to discogenic pain.

Adult↗
PubMed1993

Fluorescence resonance energy transfer within a heterochromatic cAMP-dependent protein kinase holoenzyme under equilibrium conditions: new insights into the conformational changes that result in cAMP-dependent activation.

Previous studies of the ligand regulation of the cAMP-dependent protein kinase have demonstrated the cAMP-mediated dissociation of the holoenzyme by using nonequilibrium techniques; i.e., gel filtration, ion-exchange chromatography, and differential centrifugation. While physically mild, these could have caused weakly associated species to dissociate, thereby providing a potentially flawed interpretation of the mechanism of activation of the protein kinase. To assess this, the activation of the cAMP-dependent protein kinase has been monitored under equilibrium conditions using dipolar fluorescence energy transfer to measure changes in the proximity relations between the catalytic (C) and regulatory (R) subunits that compose the holoenzyme. Specifically, we prepared a heterochromatically labeled protein kinase type II holoenzyme, with the regulatory and catalytic subunits labeled with sulforhodamine and carboxyfluorescein, respectively, and monitored the exchange of electronic excitation energy between the C and R subunits by both donor lifetime and steady-state fluorescence. Biochemically, the heterochromatic holoenzyme was closely identical to the native protein with regard to cAMP-induced increase in catalytic activity, reassociation of C and R subunits, inhibition of catalytic activity by the specific protein kinase inhibitor (PKI), and observed dissociation examined by gel filtration upon cAMP addition. However, under equilibrium conditions, the energy-transfer measurements revealed that the addition of cAMP to this heterochromatic reporter complex promoted an estimated 10-A increase in the distance between the derivatization sites on C and R but not a dissociation of these subunits. Addition of PKI plus cAMP promoted full dissociation of the two subunits.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Solution structure of the cAMP-dependent protein kinase catalytic subunit and its contraction upon binding the protein kinase inhibitor peptide.

Small-angle X-ray scattering and Fourier transform infrared (FTIR) spectroscopy experiments have been completed on the catalytic subunit of the cAMP-dependent protein kinase. Measurements were made both with and without the protein kinase inhibitor peptide, PKI alpha(5-22)amide. Binding of the peptide results in an overall contraction of the structure that is characterized by a decrease of 9% in radius of gyration and about 16% in the maximum linear dimension. Both the secondary structure content of the protein/peptide complex, as determined by FTIR, and the solution structure of this binary complex, as determined by X-ray scattering, agree well with the structural characteristics of this complex as elucidated by the crystal structure [Knighton, D.R., Zheng, J., Ten Eyck, L. F., Ashford, V.A., Xuong, N.H., Taylor, S.S., & Sowadsi, J. M. (1991a) Science 253, 407-414]. Further, the contraction of the structure observed by X-ray scattering upon inhibitor peptide binding is not accompanied by any detectable change in secondary structure content of the kinase. We have modeled the contraction of the kinase upon inhibitor peptide binding as a simple rotation of the large and small lobes seen in the crystal structure such that the cleft between them is closed. For a substrate these changes would then allow catalysis to ensue. The hinge for this movement occurs around a glycine that is one of the protein kinase family consensus amino acids.

Amino Acid Sequence↗
PubMed1993

Characterization of the gene for rat phosphorylase kinase catalytic subunit.

Phosphorylase kinase, a key enzyme in glycogen metabolism, has a subunit composition of (alpha beta gamma delta)4, in which the alpha and beta subunits are regulatory, delta is calmodulin, and the gamma subunit is catalytic. As one segment of our studies on the regulation of the expression of phosphorylase kinase subunits, we present in this report the structure of the gene for the catalytic gamma subunit. The gene extends over 16 kilobase pairs (kb) of DNA, and contains eight introns within the coding region plus one 3.3-kb intron upstream in the 5'-untranslated region. Within this first intron, and also upstream of the transcription start site, are sequences homologous to defined regulatory elements, including some found in other muscle-specific genes. The positions of intron splice junctions for this gene have been compared with similar data for other protein kinase genes. A somewhat unexpected finding for the gamma subunit is that two of the splice junctions fall in the midst of highly conserved strings of amino acids, both of which have been nominally defined as functional domains for the protein kinases and appear to make key contributions to substrate binding and phosphotransferase catalysis.

Amino Acid Sequence↗
PubMed1993

In situ regulation of cell-cell communication by the cAMP-dependent protein kinase and protein kinase C.

The effects of cAMP-dependent protein kinase A and protein kinase C on cell-cell communication have been examined in primary ovarian granulosa cells microinjected with purified components of these two regulatory cascades. These cells possess connexin43 (alpha 1)-type gap junctions, and are well-coupled electrotonically and as judged by the cell-to-cell transfer of fluorescent dye. Within 2-3 min after injection of the protein kinase A inhibitor (PKI) communication was sharply reduced or ceased, but resumed in about 3 min with the injection of the protein kinase A catalytic subunit. A similar resumption also occurred in PKI-injected cells after exposure to follicle stimulating hormone. Microinjection of the protein kinase C inhibitor protein caused a transient cessation of communication that spontaneously returned within 15-20 min. Treatment of cells with activators of protein kinase C, TPA or OAG for 60 min caused a significant reduction in communication that could be restored within 2-5 min by the subsequent injection of either the protein kinase C inhibitor or the protein kinase A catalytic subunit. With a longer exposure to either protein kinase C activator communication could not be restored and this appeared to be related to the absence of aggregates of connexin43 in membrane as detected immunologically. In cells injected with alkaline phosphatase communication stopped but returned either spontaneously within 20 min or within 2-3 min of injecting the cell with either the protein kinase A catalytic subunit or with protein kinase C. When untreated cells were injected with protein kinase C communication diminished or ceased within 5 min. Collectively these results demonstrate that cell-cell communication is regulated by both protein kinase A and C, but in a complex interrelated manner, quite likely by multiple phosphorylation of proteins within or regulating connexin-43 containing gap junctions.

Animals↗
PubMed1993

Monoarthritis in the rat knee induces bilateral and time-dependent changes in substance P and calcitonin gene-related peptide immunoreactivity in the spinal cord.

Bilateral changes in the spinal cord and dorsal root ganglion content of the sensory peptides substance P and calcitonin gene-related peptide have been previously reported in animal models of arthritis which affect many joints within the body. The central nervous system has been implicated in the symmetry of joint involvement in human rheumatoid arthritis. We aimed to determine whether unilateral inflammation of the knee joint can also induce bilateral changes in the spinal cord. We have induced a monoarthritis in the knee joint of the rat and used quantitative immunocytochemistry to look at changes of these peptides in the dorsal horn of the spinal cord and the dorsal root ganglia. Furthermore we have examined the responses during the acute (three days) and the chronic (21 days) phases of the model. The data show that in the acute phase of the monoarthritis there is both an ipsilateral and contralateral response which increases the immunoreactive substance P and calcitonin gene-related peptide in the L4 level of the dorsal horn of the spinal cord. In the chronic phase of the monoarthritis, the contralateral side of the dorsal horn returned to control values whilst the ipsilateral side showed reduced amounts of immunoreactive substance P and calcitonin gene-related peptide compared to controls. We propose that the acute response, at three days, to unilateral inflammation is appropriate and has evolved to protect an organism against the original insult ipsilaterally, and the possibility of subsequent insult contralaterally.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗