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T A Bennett

Publications and source records attributed to T A Bennett.

At least 19 recordsLinked to original sources
PubMed2002

Performance of in-line microfluidic mixers in laminar flow for high-throughput flow cytometry.

We describe a micromixing approach that is compatible with commercial autosamplers, flow cytometry, and other detection schemes that require the mixing of components that have been introduced into laminarflow. The scheme is based on high-throughput flow cytometry (HyperCyt) where samples from multi-well plates that have been picked up by an autosampler can be separated during delivery by the small air bubbles introduced during the transit of the autosampler probe from well to well. Here, either cell or particle samplesflowing continuously and driven by a syringe are brought together in a Y with reagent samples from wells driven by a peristaltic pump. The mixing is driven by a magnetic microstirrer contained within the sample line. The mixing is assessed using fluorescence of both cell calcium responses and bead-based fluorescence unquenching. In the analysis stream, the particles and reagents are mixed with eithera "wire" or "bar". The bar is more efficient than the wire, and the efficiency of either depends on the spinning action. The high-throughput approach and mixing in HyperCyt integrate autosamplers with submicroliter detection volumes for analysis in flow cytometry or in microfluidic channels.

Equipment Design↗
PubMed2001

Partial phosphorylation of the N-formyl peptide receptor inhibits G protein association independent of arrestin binding.

It is now well accepted that G protein-coupled receptors activated by agonist binding become targets for phosphorylation, leading to desensitization of the receptor. Using a series of phosphorylation deficient mutants of the N-formyl peptide receptor (FPR), we have explored the role of phosphorylation on the ability of the receptor to interact with G proteins and arrestins. Using a fluorometric assay in conjunction with solubilized receptors, we demonstrate that phosphorylation of the wild type FPR lowers its affinity for G protein, whereas mutant receptors lacking four potential phosphorylation sites retain their ability to couple to G protein. Phosphorylated mutant receptors lacking only two potential phosphorylation sites are again unable to couple to G protein. Furthermore, whereas stimulated wild type FPR in whole cells colocalizes with arrestin-2, and the solubilized, phosphorylated FPR binds arrestin-2, the stimulated receptors lacking four potential phosphorylation sites display no interaction with arrestin-2. However, the mutant receptors lacking only two potential phosphorylation sites are restored in their ability to bind and colocalize with arrestin-2. Thus, there is a submaximal threshold of FPR phosphorylation that simultaneously results in an inhibition of G protein binding and an induction of arrestin binding. These results are the first to demonstrate that less than maximal levels of receptor phosphorylation can block G protein binding, independent of arrestin binding. We therefore propose that phosphorylation alone may be sufficient to desensitize the FPR in vivo, raising the possibility that for certain G protein-coupled receptors, desensitization may not be the primary function of arrestin.

Amino Acid Sequence↗
PubMed2001

Regulation of formyl peptide receptor agonist affinity by reconstitution with arrestins and heterotrimeric G proteins.

Although heptahelical chemoattractant and chemokine receptors are known to play a significant role in the host immune response and the pathophysiology of disease, the molecular mechanisms and transient macroassemblies underlying their activation and regulation remain largely uncharacterized. We report herein real time analyses of molecular assemblies involving the formyl peptide receptor (FPR), a well described member of the chemoattractant subfamily of G protein-coupled receptors (GPCRs), with both arrestins and heterotrimeric G proteins. In our system, the ability to define and discriminate distinct, in vitro receptor complexes relies on quantitative differences in the dissociation rate of a fluorescent agonist as well as the guanosine 5'-3-O-(thio)triphosphate (GTP gamma S) sensitivity of the complex, as recently described for FPR-G protein interactions. In the current study, we demonstrate a concentration- and time-dependent reconstitution of liganded, phosphorylated FPR with exogenous arrestin-2 and -3 to form a high agonist affinity, nucleotide-insensitive complex with EC(50) values of 0.5 and 0.9 microm, respectively. In contrast, neither arrestin-2 nor arrestin-3 altered the ligand dissociation kinetics of activated, nonphosphorylated FPR. Moreover, we demonstrated that the addition of G proteins was unable to alter the ligand dissociation kinetics or induce a GTP gamma S-sensitive state of the phosphorylated FPR. The properties of the phosphorylated FPR were entirely reversible upon treatment of the receptor preparation with phosphatase. These results represent to our knowledge the first report of the reconstitution of a detergent-solubilized, phosphorylated GPCR with arrestins and, furthermore, the first demonstration that phosphorylation of a nonvisual GPCR is capable of efficiently blocking G protein binding in the absence of arrestin. The significance of these results with respect to receptor desensitization and internalization are discussed.

Alkaline Phosphatase↗
PubMed2001

Epidermal growth factor receptor signaling and the invasive phenotype of ovarian carcinoma cells.

BACKGROUND: Most (70%-100%) ovarian carcinomas express high levels of the epidermal growth factor receptor (EGFR). To examine the relationship between EGFR and the invasive phenotype, we assessed integrin expression, adhesion, matrix metalloproteinase (MMP) activity, and migration in ovarian cancer cells in which EGFR expression was modified. METHODS: NIH:OVCAR-8 human ovarian carcinoma cells were transfected with an expression vector containing the human EGFR complementary DNA in an antisense orientation (EGFR-antisense cells) or the vector alone (vector control cells). We compared vector control and EGFR-antisense cells for cell morphology and adhesion by light microscopy, expression of alpha(6)- and alpha(3)-integrin subunits by flow cytometry, MMP and tissue inhibitor of MMP (TIMP) activity by zymography, and migration by a wound migration assay. In some experiments, EGFR kinase activity in parental cells was inhibited by treatment with PD153035. All statistical tests were two-sided. RESULTS: EGFR-antisense cells were morphologically distinct from vector control cells and had a selective decrease in adhesion to laminin-1 that was not observed with vector control cells (P = .008) or on other extracellular matrix substrates. Compared with vector control cells, cell surface alpha(6)-integrin expression decreased by approximately 80% (difference = 78.7%; 95% confidence interval [CI] = 77.8% to 79.6), MMP-9 activity decreased by approximately 50%, and TIMP activity increased by approximately 50% in EGFR-antisense cells. Vector control cells were highly motile (5.51 arbitrary distance unit; 95% CI = 4.98 to 6.04), whereas the EGFR-antisense cells were not (0.99 arbitrary distance units; 95% CI = 0.38 to 1.60). The morphology and integrin profile of NIH:OVCAR-8 parental cells treated with PD153035 were similar to those of the EGFR-antisense cells. CONCLUSIONS: Reduced EGFR expression in ovarian carcinoma cells decreased their adhesion to laminin-1, expression of the alpha(6)-integrin subunit (a well-characterized laminin-1 receptor), and MMP-9 activity. These data support the hypothesis that EGFR overexpression in ovarian cancer cells results in multiple phenotypic changes that enhance the invasive phenotype.

Antigens, CD↗
PubMed2001

Real-time analysis of G protein-coupled receptor reconstitution in a solubilized system.

Receptor based signaling mechanisms are the primary source of cellular regulation. The superfamily of G protein-coupled receptors is the largest and most ubiquitous of the receptor mediated processes. We describe here the analysis in real-time of the assembly and disassembly of soluble G protein-coupled receptor-G protein complexes. A fluorometric method was utilized to determine the dissociation of a fluorescent ligand from the receptor solubilized in detergent. The ligand dissociation rate differs between a receptor coupled to a G protein and the receptor alone. By observing the sensitivity of the dissociation of a fluorescent ligand to the presence of guanine nucleotide, we have shown a time- and concentration-dependent reconstitution of the N-formyl peptide receptor with endogenous G proteins. Furthermore, after the clearing of endogenous G proteins, purified Galpha subunits premixed with bovine brain Gbetagamma subunits were also able to reconstitute with the solubilized receptors. The solubilized N-formyl peptide receptor and Galpha(i3) protein interacted with an affinity of approximately 10(-6) m with other alpha subunits exhibiting lower affinities (Galpha(i3) > Galpha(i2) > Galpha(i1) Galpha(o)). The N-formyl peptide receptor-G protein interactions were inhibited by peptides corresponding to the Galpha(i) C-terminal regions, by Galpha(i) mAbs, and by a truncated form of arrestin-3. This system should prove useful for the analysis of the specificity of receptor-G protein interactions, as well as for the elucidation and characterization of receptor molecular assemblies and signal transduction complexes.

Animals↗
PubMed2001

Internalization of the human N-formyl peptide and C5a chemoattractant receptors occurs via clathrin-independent mechanisms.

After stimulation by ligand, most G protein-coupled receptors (GPCRs) undergo rapid phosphorylation, followed by desensitization and internalization. In the case of the N-formyl peptide receptor (FPR), these latter two processing steps have been shown to be entirely dependent on phosphorylation of the receptor's carboxy terminus. We have previously demonstrated that FPR internalization can occur in the absence of receptor desensitization, indicating that FPR desensitization and internalization are regulated differentially. In this study, we have investigated whether human chemoattractant receptors internalize via clathrin-coated pits. Internalization of the FPR transiently expressed in HEK 293 cells was shown to be dependent upon receptor phosphorylation. Despite this, internalization of the FPR, as well as the C5a receptor, was demonstrated to be independent of the actions of arrestin, dynamin, and clathrin. In addition, we utilized fluorescence microscopy to visualize the FPR and beta(2)-adrenergic receptor as they internalized in the same cell, revealing distinct sites of internalization. Last, we found that a nonphosphorylatable mutant of the FPR, unable to internalize, was competent to activate p44/42 MAP kinase. Together, these results demonstrate not only that the FPR internalizes via an arrestin-, dynamin-, and clathrin-independent pathway but also that signal transduction to MAP kinases occurs in an internalization-independent manner.

Antigens, CD↗
PubMed2001

Tissue inhibitor of metalloproteinase-1 alters the tumorigenicity of Burkitt's lymphoma via divergent effects on tumor growth and angiogenesis.

Epstein-Barr virus (EBV)-positive Burkitt's lymphoma cells and EBV-infected B cells elicit humoral factors that inhibit tumor-induced angiogenesis, resulting in tumor necrosis and regression. Of the chemokine factors identified in association with this growth behavior, none have induced complete tumor regression. We have previously identified tissue inhibitors of metalloproteinase (TIMP)-1 in various B cell lymphoma cell lines. Here we show that induction of TIMP-1 expression in an EBV-negative Burkitt's lymphoma cell line results in a biphasic, in vivo tumor growth pattern in the nude mouse that is essentially identical to EBV-positive Burkitt's lymphoma cell lines. The initial effect of TIMP-1 is to enhance tumor growth, consistent with the reported anti-apoptotic effect of TIMP-1 on B cell growth. Tumor necrosis and regression then follow the initial period of rapid, increased tumor growth. Only microscopic foci of residual, proliferating tumor cells are observed on biopsy of the tumor site. This latter effect is mediated by TIMP-1 inhibition of an angiogenic response within the developing tumor mass, as demonstrated by immunostaining and microvessel counts. These findings suggest that TIMP-1 is an important mediator of the in vivo growth properties of EBV-positive Burkitt's lymphoma.

Animals↗
PubMed2000

Arrestin binding to the G protein-coupled N-formyl peptide receptor is regulated by the conserved "DRY" sequence.

Following activation by ligand, the N-formyl peptide receptor (FPR) undergoes processing events initiated by phosphorylation that lead to receptor desensitization and internalization. Our previous results have shown that FPR internalization can occur in the absence of receptor desensitization, suggesting that FPR desensitization and internalization are controlled by distinct mechanisms. More recently, we have provided evidence that internalization of the FPR occurs via a mechanism that is independent of the actions of arrestin, dynamin, and clathrin. In the present report, we demonstrate that stimulation of the FPR with agonist leads to a significant translocation of arrestin-2 from the cytosol to the membrane. Fluorescence microscopy revealed that the translocated arrestin-2 is highly colocalized with the ligand-bound FPR. A D71A mutant FPR, which does not undergo activation or phosphorylation in response to ligand, did not colocalize with arrestin-2. Surprisingly, an R123G mutant FPR, which does not bind G protein but does become phosphorylated and subsequently internalized, also did not bind arrestin. These results indicate that arrestin binding is not required for FPR internalization and demonstrate for the first time that a common motif, the conserved "DRY" domain of G protein-coupled receptors, is essential for phosphorylation-dependent arrestin binding, as well as G protein activation.

Amino Acid Sequence↗
PubMed2000

Sulfhydryl regulation of L-selectin shedding: phenylarsine oxide promotes activation-independent L-selectin shedding from leukocytes.

The L-selectin adhesion molecule mediates leukocyte recruitment to inflammatory sites and lymphocyte trafficking through the peripheral lymph nodes. In response to leukocyte activation, L-selectin is proteolytically released from the cell surface, disabling leukocytes from the subsequent L-selectin-dependent interactions. We have found that L-selectin shedding is sensitive to sulfhydryl chemistry; it is promoted by thiol-oxidizing or -blocking reagents and inhibited by reducing reagents. Phenylarsine oxide (PAO), a trivalent arsenical that interacts with vicinal dithiols, is most potent in inducing rapid shedding of L-selectin from isolated neutrophils, eosinophils, and lymphocytes as well as from neutrophils in whole blood. PAO does not cause cell activation, nor does it interfere with integrin function or alter the expression of several other cell surface molecules at the low concentrations that induce L-selectin shedding. PAO is not required to enter the cell to induce L-selectin shedding. TAPI-2 ((N-(D,L-[2-(hydroxyaminocarbonyl)-methyl]-4-methylpentanoyl)-L-3-(tert-butyl)-alanyl-l -alanine, 2-aminoethyl amide), which has previously been shown to inhibit the activation-dependent L-selectin shedding, is also capable of inhibiting PAO-induced L-selectin shedding. We hypothesize that PAO-induced L-selectin shedding involves a regulatory molecule, such as protein disulfide isomerase (PDI), an enzyme that plays a role in the formation and rearrangement of disulfide bonds, contains PAO-binding, vicinal dithiol-active sites, and is expressed on the neutrophil surface. Cell surface expression of PDI, L-selectin shedding induced by PDI-blocking Abs and by bacitracin, a known inhibitor of PDI activity, and direct binding of PDI to PAO, provide supporting evidence for this hypothesis.

Arsenicals↗
PubMed2000

Solubilization and display of G protein-coupled receptors on beads for real-time fluorescence and flow cytometric analysis.

G protein-coupled receptors (GPCR) and cellular signaling elements are prime targets for drug discovery. Sensitive real-time methods that expand the analytical capabilities for these elements can play significant roles in basic research and drug discovery. Here, we describe novel approaches for the real-time fluorescence analysis of GPCRs. Using the G protein-coupled N-formyl peptide receptor (FPR) as a model system in concert with a fluorescent ligand, we showed the quantitative solubilization of his-tagged FPRs in 1% dodecyl maltoside. Solubilized receptors reconstitute in dodecyl maltoside with a mixture of bovine brain Gi/Go showing an apparent Kd of 100 nM. Solubilized receptors were also bound to Ni(2+)-silica particles and were detected in a flow cytometer by the binding of fluorescent ligand. The efficiency of receptor uptake by the particles was in excess of 80% with an apparent affinity for the bead in the nM range. The receptors had largely homogeneous dissociation characteristics, an appropriate Kd for the ligand in the low nM range and a high site number, with several million receptor molecules per particle. However, the G protein reconstitution was not detected on the beads, apparently for steric reasons. These approaches for displaying receptors could prove useful in drug discovery and in the analysis of the molecular assemblies in signal transduction.

Chemotactic Factors↗
PubMed1998

Pregnancy-associated hospitalizations in the United States in 1991 and 1992: a comprehensive view of maternal morbidity.

OBJECTIVE: Our purpose was to update the national estimate of severe pregnancy complications and describe associated maternal characteristics of hospitalizations during pregnancy, applying an expanded definition of maternal morbidity. STUDY DESIGN: From 1991 and 1992 National Hospital Discharge Survey data, we estimated ratios of hospitalizations per 100 deliveries and compared relative ratios by maternal characteristics. We computed standard errors with the SUDAAN program and estimated 95% confidence intervals for relative ratios. RESULTS: The likelihood of hospitalization for pregnancy complications appeared to decline between the period 1986 and 1987 and the period 1991 and 1992, although primarily for pregnancy loss hospitalizations. In 1991 and 1992 there were 18.0 total pregnancy-associated hospitalizations/100 births (17.2 for whites, 28.1 for blacks). Component ratios were 12.3 for obstetric hospitalizations, 4.4 for pregnancy loss hospitalizations, and 1.4 for nonobstetric hospitalizations; all ratios were higher for blacks than for whites. CONCLUSIONS: Maternal hospitalization remains a substantial component of prenatal care. Because of underreporting and changes in medical practice, recent declines in maternal hospitalization may not represent true reductions in maternal morbidity.

Abortion, Spontaneous↗
PubMed1997

Programs and services to prevent pregnancy, childbearing, and poor birth outcomes among adolescents in rural areas of the southeastern United States.

PURPOSE: To illustrate how rural adolescents' needs for pregnancy prevention and improved birth outcomes are currently being addressed, and to suggest strategies for future programs. METHODS: Local and state-level informants knowledgeable about services to adolescents in the Southeastern United States were identified. Semistructured interviews were used to determine the program start date and time frame, funding sources, target population, participating counties, implementing agency or organization, specific program services, and status of program activities. These programs were categorized by the type of services offered and the population targeted. RESULTS: The most common adolescent services in the rural Southeast attempt either to improve life options of youth, reduce sexual activity, or provide prenatal and postnatal care. Unlike urban areas where there are a variety of family planning providers, in the rural Southeast, health departments are the primary source of family planning for adolescents. There are no abortion providers in most rural areas of the Southeast. The majority of rural programs that include adolescents among the population served are developed for all women rather than specifically for adolescents. Programs specific to rural adolescents are described. CONCLUSIONS: The majority of programs in the rural Southeast address only selected adolescent health issues. Successful interventions require locally supported, multipronged, intensive approaches with consistent messages targeted to high-risk populations. Evaluation tools are needed to determine the effectiveness of each component of prevention programs.

Adolescent↗
PubMed1996

Mobilization of CD34+ progenitor cells by granulocyte colony-stimulating factor in human immunodeficiency virus type 1-infected adults.

We conducted a clinical trial to determine the feasibility of growth factor mobilization of CD34+ progenitor cells in human immunodeficiency virus type 1 (HIV-1)-infected individuals. Eight asymptomatic, HIV-1-infected adults (median CD4+ T-cell count, 415 cells/microL), received 480 micrograms/d of granulocyte colony-stimulating factor (G-CSF) for 6 days without evidence of viral activation. Despite concerns that HIV-1 might inhibit hematopoiesis, CD34+ cells were successfully mobilized to the periphery of all donors, independent of the baseline CD4+ T-cell count, and the status of antiretroviral therapy. Leukapheresis was performed on day 6, and yielded a median of 194 x 10(6) CD34+ cells per leukapheresis (n = 7). CD34-enriched cells from the leukapheresis were predominantly myeloid-committed, but between 0.2% and 1.7% were primitive CD34+/CD38- progenitors. A median of 21.7% of the mobilized CD34+ cells were dimly positive for CD4. Consequently, CD34(+)-enriched cells were purified on the cell sorter (mean purity, 97.7% +/- 2.4%; n = 7), and examined for HIV-1 DNA. Purified CD34+ cells from two of seven donors were polymerase chain reaction (PCR)-positive for HIV-1, but only from one of three samples from each donor. We conclude that G-CSF can safely mobilize CD34+ progenitor cells in HIV-1-infected subjects, and that these cells are suitable for consideration in gene-transfer strategies.

Adult↗
PubMed1996

Hydroxamate-based metalloprotease inhibitor blocks shedding of L-selectin adhesion molecule from leukocytes: functional consequences for neutrophil aggregation.

L-selectin is an adhesion molecule that mediates the recruitment of neutrophils to inflammatory sites and initiates the migration of lymphocytes into the peripheral lymph nodes. In response to cell activation, L-selectin is shed from the cell surface, and altered levels of functional soluble L-selectin are detected in the plasma of patients suffering from numerous inflammatory diseases as well as AIDS. The mechanism that regulates L-selectin shedding is poorly understood. Here we show that a hydroxamate-based metalloprotease inhibitor, N-(D,L-[2-(hydroxyaminocarbonyl)- methyl]-4-methylpentano)-L-3-(tert-butyl)-alanyl-L-alanine, 2-aminoethyl amide, which blocks leukocyte TNF, TNF receptor, and IL-6 receptor release, also inhibits L-selectin shedding from neutrophils, eosinophils, and lymphocytes. Moreover, we show that such inhibition of L-selectin shedding profoundly affects neutrophil aggregation and permits reaggregation in the presence of a heterologous stimulus.

Cell Aggregation↗
PubMed1995

Evidence for a third component in neutrophil aggregation: potential roles of O-linked glycoproteins as L-selectin counter-structures.

The homotypic aggregation of neutrophils requires the participation of L-selectin and the beta 2-integrins, but it has not been clear whether the two receptors recognize one another as counter-structures or whether other adhesion molecules are involved. We have examined aggregation of live neutrophils with target populations, manipulated to alter expression of adhesive epitopes, using flow cytometry. A target population depleted of both L-selectin and activatable beta 2-integrin displayed an ability to aggregate with live neutrophils, suggesting that these two molecules are not counter-structures. We also found that an O-sialoglycoprotease (GCP) from Pasteurella haemolytica is capable of inhibiting homotypic aggregation. Neutrophils treated with GCP lose O-glycosylated proteins but retain L-selectin and activatable beta 2-integrin. One or more of the GCP substrates appears to function in L-selectin-dependent binding but not in beta 2-integrin-dependent binding. Together the data suggest a mechanism of aggregation that is analogous to leukocyte-endothelial cell adhesion in which a low-affinity carbohydrate-dependent interaction precedes a high-affinity integrin-dependent adhesion.

Cell Adhesion Molecules↗
PubMed1995

Changes in the macrophage population of the rat superior cervical ganglion after postganglionic nerve injury.

Following peripheral nerve transection, a series of biochemical changes occurs in axons and Schwann cells both at the site of the lesion and distal to it. Macrophages differentiated from monocytes that invade the area in response to transection (elicited macrophages) and, perhaps, also macrophages normally present in the tissue (resident macrophages) play important roles in these changes. In addition, nerve transection produces changes in the cell bodies of axotomized neurons and their surrounding glial cells, located at some distance from the lesion. To determine whether macrophages might play a role in the changes occurring in the superior cervical ganglion (SCG) after axotomy, we examined the presence of macrophages before and after axonal damage. The monoclonal antibodies ED1, ED2, and OX6 were used, each of which recognizes a somewhat different population of macrophages. Ganglia from normal rats contained a population of resident cells that were ED2+ but very few that were ED1+. Within 2 days after the post-ganglionic nerves were transected, the number of ED1+ cells increased substantially, with little change in immunostaining for ED2. These data, in combination with published studies on other tissues, suggest that ED1 in the SCG is selective for elicited macrophages and ED2 for resident macrophages. OX6 immunostaining was prominent in normal ganglia but also increased significantly after axotomy, suggesting that it reflects both macrophage populations. Systemic administration of 6-hydroxydopamine, a neurotoxin that causes the destruction of sympathetic nerve endings, also produced an increase in ED1 immunostaining. Thus, the change in ED1 immunostaining in the SCG does not require surgery, with the attendant severing of local blood vessels and connective tissue, but rather only the disconnection of sympathetic neurons from their end organs. The time course of the invasion of monocytes after axotomy indicates that this process is not required to trigger the biochemical changes occurring in the ganglion within the first 24 h. On the other hand, the existence of a resident population of macrophages raises the possibility that changes in those cells might be involved.

Animals↗
PubMed1994

Galanin expression increases in adult rat sympathetic neurons after axotomy.

Changes in neuropeptide expression occur in sensory, motor, and sympathetic neurons following axotomy. The particular pattern of peptide changes that occurs varies among the three cell types. We have studied the regulation in the rat superior cervical ganglion of the expression of galanin, a peptide previously shown to increase in axotomized sensory and motor neurons. While normally only an occasional neuron exhibiting galanin-like immunoreactivity is found in this ganglion, at two days after transection of the postganglionic internal and external carotid nerves, immunostaining can be observed in many neurons throughout the ganglion. Similar changes are found when ganglia are placed in organ culture for two days. The distribution of immunostained neurons after section of only one of the postganglionic trunks suggests that changes in galanin-like immunoreactivity occur only within neurons whose axons are transected. None the less, even when both nerve trunks are transected, only about half of the neurons in the ganglion exhibit galanin-like immunoreactivity, indicating that only a proportion of the axotomized neurons exhibit a detectable response. The few immunostained neurons seen after section of the cervical sympathetic trunk may also represent axotomized neurons. Galanin-like immunoreactivity extracted from the ganglion co-chromatographs with authentic galanin, and the level of this immunoreactivity increases dramatically after axotomy and explantation, and modestly after decentralization. These same manipulations produce parallel increases in the level of galanin messenger RNA. Together, the findings indicate that the expression of galanin increases in sympathetic neurons after axotomy. Galanin is thus the first neuropeptide whose expression has been shown to increase after transection of all three types of peripheral axons that have been studied.

Animals↗