Localization of the gene responsible for the op (osteopetrotic) defect in rats on chromosome 10

Osteopetrosis, a skeletal disorder of inadequate bone resorption with an abnormal increase in skeletal mass, results from a variety of independent single gene mutations that affect osteoclast differentiation and/or function. The osteopetrotic defect, op, is one of four spontaneous, nonallelic mutations in rats that result in osteopetrosis. In intercross progeny of (BN/SsN x LEW/SsN. +/op) F1 carriers, we mapped this locus by linkage analysis with microsatellite markers to rat chromosome 10. The linkage group contained, as well as op, 15 anonymous DNA loci and 9 DNA loci associated with genes (interleukin-3, myosin heavy chain [skeletal, embryonic], asialoglycoprotein receptor [hepatic lectin]-1, vesicle-associated membrane protein [synaptobrevin-2], sex hormone binding globulin, aldolase C, nitric oxide synthase [inducible], erythroblastic leukemia avian viral oncogene homolog-2, and proline-rich protein). The markers for these loci include nine not previously reported. The op locus mapped to the end of the chromosome 10 linkage group, within 1 cM of the anonymous DNA locus, D10Mit6. Based on its location, the op gene is likely to be distinct from seven described mutations in mice as well as three other mutations in rats. These results may permit a positional cloning strategy to be undertaken to identify the gene and mutation underlying the op defect.

Genetic maps of polymorphic DNA loci on rat chromosome 1

Genetic linkage maps of loci defined by polymorphic DNA markers on rat chromosome 1 were constructed by genotyping F2 progeny of F344/N x LEW/N, BN/SsN x LEW/N, and DA/Bkl x F344/Hsd inbred rat strains. In total, 43 markers were mapped, of which 3 were restriction fragment length polymorphisms and the others were simple sequence length polymorphisms. Nineteen of these markers were associated with genes. Six markers for five genes, gamma-aminobutyric acid receptor beta3 (Gabrb3), syntaxin 2 (Stx2), adrenergic receptor beta1 (Adrb1), carcinoembryonic antigen gene family member 1 (Cgm1), and lipogenic protein S14 (Lpgp), and 20 anonymous loci were not previously reported. Thirteen gene loci (Myl2, Aldoa, Tnt, Igf2, Prkcg, Cgm4, Calm3, Cgm3, Psbp1, Sa, Hbb, Ins1, and Tcp1) were previously mapped. Comparative mapping analysis indicated that a large portion of rat chromosome 1 is homologous to mouse chromosome 7, although the homologs of two rat genes are located on mouse chromosomes 17 and 19. Homologs of the rat chromosome 1 genes that we mapped are located on human chromosomes 6, 10, 11, 12, 15, 16, and 19.

Linkage maps of rat chromosomes 15, 16, 17, 19, and X

Linkage maps of rat chromosomes 15, 16, 17, 19, and X were constructed by multipoint genetic linkage analysis of 22 polymorphic markers in 40 F2 progeny of Fischer (F344/N) and Lewis (LEW/N) inbred rat strains. These markers are associated with eight genes (angiotensin receptor A, M3 muscarinic acetylcholine receptor, heme oxygenase, endothelin receptor A, haptoglobin, tyrosine aminotransferase, phosphoribosylpyrophosphate synthetase subunit II, and 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase) and 14 anonymous loci. Linkage analysis placed the markers into five linkage groups covering 11.7,7.9,11.6,42.5, and 5.1cM. These linkage groups were assigned to rat chromosomes 15, 16, 17, 19, and X, respectively, either by mouse x rat somatic cell hybrid analysis or based on previously identified locations of severalloci. In polymorphism analysis, these markers exhibited two to nine different alleles in 16 inbred rat strains.

Genetic map of 16 polymorphic markers forming three linkage groups assigned to rat chromosome 4

Sixteen polymorphic markers, including markers for eight new loci, forming three linkage groups, were assigned to rat Chromosome (Chr) 4 by linkage analysis of the progeny of an F2 intercross of Fischer (F344/N) and Lewis (LEW/N) inbred rats. One gene, Igk, was mapped by restriction fragment length polymorphism (RFLP) analysis. One marker for Tcrb was identified by the polymorphic insertion of a repetitive LINE element. The remaining 14 markers contained polymorphic simple sequence repeats (SSRs). Ten were identified in genes (Tgfa, Npy, Prss1, Prss2, Aldr1, Iapp, Prp, Eno2, Cacnl1a1, and Il6), one was identified in a sequence related to a gene (Egr4l1), and three were identified in anonymous DNA segments. The SSR markers were highly polymorphic in 16 inbred rat strains. These markers expand the genetic map of the rat and should be useful in future genetic studies of inbred rats.

A genetic map of microsatellite markers on rat chromosome 7

Nine microsatellite loci were mapped to rat Chromosome (Chr) 7 by genetic linkage and somatic cell hybrid analysis. These loci include the gene encoding a member of the IID sub-family of cytochrome P450 (Cyp2d), a gene with repetitive sequences expressed during myotube formation (D7Arb1e), four anonymous loci, D7Arb81, D7Arb208, D7Arb569, D7Arb609a, and three DNA loci defined by MapPair markers R245, R513, and R1071. The nine loci were all identified by PCR-based microsatellite polymorphism analysis and were characterized in 40 F2 intercross progeny of Fischer (F344/N) and Lewis (LEW/N) rats for segregation analysis. These markers formed a single linkage group spanning 76.8 cM with the following order and distances: D7Arb569-11.4 cM-D7Arb81-9.7 cM-R513-2.6 cM-Cyp2d-0.0 cM-R245-1.3 cM-D7Arb1e-10.4 cM-R1071-15.9 cM-D7Arb609a-15.4 cM-D7Arb208. Physical mapping of Cyp2d by somatic cell hybrid analysis allowed us to assign this linkage group to rat Chr 7. For each marker, two to six alleles were detected in a panel of 16 inbred rat strains (ACI/N, BN/SsN, BUF/N, DA/Bkl, F344/N, LER/N, LEW/N, LOU/MN, MNR/N, MR/N, SHR/N, SR/Jr, SS/Jr, WBB1/N, WBB2/N, WKY/N).

Genetic map of eight microsatellite markers comprising two linkage groups on rat chromosome 6

Five genes and three anonymous DNA loci were mapped to rat chromosome 6 by genetic linkage and somatic cell hybrid analyses. The eight loci were all identified by PCR-based microsatellite polymorphism analysis and were characterized in 40 F2 intercross progeny of Fischer (F344/N) and Lewis (LEW/N) inbred rats for segregation analysis. These markers formed two linkage groups spanning, respectively, 58.1 cM and 4.0 cM. The first linkage group is comprised of two anonymous DNA loci and four genes with the following map order and distances: D6Cep8 (previously D3)-17.9 cM-D6Arb309-2.5 cM-Vsnl1 (neural visinin-like protein)-20.4 cM-Prkar2b (type IIb regulatory subunit of cAMP-dependent protein kinase)-8.8 cM-Fkhl1 (forkhead-like transcription factor BF-1)-8.5 cM-Rnu1c (18-3A U1 RNA). The second linkage group is comprised of one gene, Ckb (creatine kinase, brain) and one anonymous DNA locus, D6Arb54, separated by 4.0 cM. For each marker, two to eight alleles were detected in a panel of 16 inbred rat strains (ACI/N, BN/SsN, BUF/N, DA/Bk1, F344/N, LER/N, LEW/N, LOU/MN, MNR/N, MR/N, SHR/N, SR/Jr, SS/Jr, WBB1/N, WBB2/N, and WKY/N). Comparative mapping information indicated that rat chromosome 6 exhibits syntenic conservation with mouse chromosome 12. Homologs of the rat chromosome 6 loci have been identified on human chromosomes 2, 7, and 14.

A single linkage group comprising 11 polymorphic DNA markers on rat chromosome 3

Eleven polymorphic DNA markers were mapped to rat Chromosome (Chr) 3 by linkage analysis of F2 progeny of F344/N and LEW/N rat strains. The markers, including seven genes and four anonymous loci, formed a single linkage group covering approximately 112 cM with the following order: Ptgs1 (prostaglandin G/H synthase I)-D3Arb178-Scn2a (sodium channel, type II, alpha-polypeptide)-D3Arb1-Cat (catalase)-Bdnf (brain-derived neurotropic factor)-D3Arb219-D3Arb2-Sus2 (seminal vesicle secretion II protein)-Sdc4 (ryudocan/syndecan4)-Stn1 (statin-like protein). Eight of these markers were analyzed for polymorphisms in 14 additional inbred rat strains. Three to five alleles were detected for each marker, suggesting that they are highly polymorphic and useful for genetic mapping studies with inbred rat strains. Chromosomal syntenic conservation among rats, mice and humans is also discussed.

Simple sequence repeat length polymorphisms mapped to rat chromosome 11

Two genes and two anonymous DNA loci were mapped to rat chromosome 11 using F2 intercross progeny of Fischer (F344/N) and Lewis (LEW/N) inbred rats. These four loci formed a single linkage group covering 21.5 cM with the following map order: somatostatin (SST)-D11N161-D11N18-cell surface protein (MOX2). These four loci were typed by PCR-based simple sequence repeat (SSR) length polymorphism detection. For each marker four to seven different alleles were detected using a panel of 13 inbred rat strains (F344/N, LEW/N, BN/SsN, BUF/N, LER/N, MR/N, MNR/N, LOU/MN, ACI/N, WBB1/N, WBB2/N, SHR/N, WKY/N). Comparative gene mapping analysis suggests syntenic conservation between rat chromosome 11 and mouse Chromosome 16.

Nine polymorphic markers characterized by polymerase chain reaction techniques form two linkage groups on rat chromosome 8

Five genes and four anonymous polymorphic markers, forming two linkage groups, were mapped in F2 intercross progeny of F344/N x LEW/N rats using polymerase chain reaction (PCR) techniques. Both linkage groups were assigned to rat chromosome 8 because they contained genetic loci previously mapped to this chromosome. The first group was comprised of markers for three anonymous loci and two gene loci, thymus cell antigen-1 (Thy1) and tropoelastin (Eln). The second group was comprised of markers for one anonymous locus and three gene loci, cellular retinol binding protein II (Rbp2), matrin F/G (Matr1), and acyl-peptide hydrolase (Apeh). Seven markers (identified by simple sequence repeat associated length polymorphisms) were characterized in an additional 13 inbred rat strains (ACI/N, BN/SsN, BUF/N, LER/N, LOU/MN, MNR/N, MR/N, SHR/N, SR/Jr, SS/Jr, WBB1/N, WBB2/N, and WKY/N). Two to six alleles were detected for each marker. The reported markers should facilitate genetic mapping and monitoring of inbred rat strains.

Genetic map of seven polymorphic markers comprising a single linkage group on rat chromosome 5

Seven polymorphic markers comprising a single linkage group were assigned to rat Chromosome (Chr) 5 by linkage analysis of the progeny of an F2 intercross of Fischer (F344/N) and Lewis (LEW/N) inbred rats. Three genes, alpha-L-fucosidase 1 (FUCA1), mitochondrial superoxide dismutase (SOD2), and glucose transporter (GLUT1), were mapped by restriction fragment length polymorphism (RFLP) analysis. Two genes, glucose transporter (GTG3) and elastase II (ELAII), one pseudogene for alpha tubulin (TUBAPS), and one sequence related to the 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase gene (PFKFBP1-related sequence) were mapped by simple sequence repeat (SSR) polymorphism analysis. The loci are in the following order: SOD2, GTG3/GLUT1, FUCA1, ELAII/PFKFBP1-related sequence, and TUBAPS. This linkage group covered 68.3 cM of rat Chr 5. The SSR markers were highly polymorphic in 13 inbred rat strains (SHR/N, WKY/N, MNR/N, MR/N, LOU/MN, BN/SsN, BUF/N, WBB1/N, WBB2/N, ACI/N, LER/N, F344/N, and LEW/N). These markers, located on rat Chr 5, will be useful in genetic studies of inbred rats.

Linkage map of nine loci defined by polymorphic DNA markers assigned to rat chromosome 13

A genetic map of nine loci defined by polymorphic DNA markers was created using a single cross of F344/N and LEW/N rats. The markers contained polymorphic simple sequence repeats identified in five genes, renin (Ren), cardiac troponin T (Tnnt3), synaptotagmin (Syt2), Na+,K(+)-ATPase catalytic subunit (Atp1a2), and the Asp-, Gly-, Glu-, and Leu-tRNA gene cluster (Trnegl), as well as four anonymous DNA segments. Analysis of the segregation of the alleles of these markers in F2 intercross progeny of F344/N and LEW/N rats indicated the following locus order and distances between pairs of loci: D13N1-5 cM-Ren-1 cM-Tntt3-0 cM-Syt2-12 cM-D13N2-25 cM-Atp1a2-0 cM-Trnegl-7 cM-D13N3-4 cM-D13N4. Three of the loci, Ren, Trnegl, and Atp1a2, have previously been assigned to rat chromosome 13. Except for Ren, none of the loci have previously been mapped by linkage analysis. The markers for these loci were characterized in a total of 13 inbred rat strains (F344/N, LEW/N, LOU/MN, WBB1/N, WBB2/N, MR/N, MNR/N, ACI/N, SHR/N, WKY/N, BN/SsN, BUF/N, and LER/N) and were found to be highly polymorphic, with two to eight alleles detected for each marker. These markers expand the genetic map of the rat and should be valuable tools for future genetic studies. An examination of human and mouse comparative map information for all loci assigned to rat chromosome 13 shows significant synteny conservation with the q arm of human chromosome 1 and the distal portion of mouse chromosome 1.

Four polymorphic markers on rat chromosome 12 form a single linkage group

Four PCR-typable polymorphic markers were mapped to rat chromosome 12 by linkage analysis of F2 intercross progeny of Fischer (F344/N) and Lewis (LEW/N) rat strains. The markers formed a single linkage group, covering 27.7 cM, with the following order and distance between markers: plasminogen activator inhibitor (Planh)--0.0 cM--phosphoenolpyruvate carboxykinase-related sequence 2 (Pepckr2)--15.4 cM--anonymous marker (D12N155)--12.3 cM--serine dehydratase (Sdh). All markers were identified and genotyped by PCR analysis of simple sequence repeats. The gene encoding Planh was previously assigned to rat chromosome 12, which allowed us to assign the entire linkage group to this chromosome. These markers were highly polymorphic in 13 additional inbred rat strains (BUF/N, BN/SsN, WKY/N, MNR/N, LER/N, WBB1/N, WBB2/N, MR/N, LOU/MN, SHR/N, ACI/N, SR/Jr, and SS/Jr). These markers should be useful tools for further genetic studies in rats.

Genetic map of 12 polymorphic loci on rat chromosome 1

Twelve polymorphic markers identified by restriction fragment length polymorphism (RFLP) analysis or simple sequence repeat (SSR) polymorphism analysis were assigned to rat chromosome 1 by linkage analysis of F2 intercross progeny of F344/N and LEW/N inbred rat strains. One linkage group, covering 46.3 cM, consisted of eight markers including five genes, TNT (fast skeletal troponin T), IGF2 (insulin-like growth factor 2), MYL2 (MLC2 gene for muscle myosin light chain 2), ALDOA (aldolase A), and HBB (hemoglobin beta-chain); one anonymous locus, D1N64; one marker related to the carboxypeptidase B gene, CARB07-related sequence; and one marker related to the parathyroid hormone gene, PTH-related sequence. A second linkage group, covering 45.0 cM, consisted of three markers including two anonymous loci, 2B1 and D1N40, and one gene, TCP1 (T-complex 1). INS1 (insulin 1), which has been previously assigned to rat chromosome 1, was not linked to these markers. The SSR markers were highly polymorphic in 13 inbred rat strains (SHR/N, WKY/N, MNR/N, MR/N, LOU/MN, BN/SsN, BUF/N, WBB1/N, WBB2/N, ACl/N, LER/N, F344/N, and LEW/N). These markers, located on chromosome 1, will be useful in genetic studies in rats.

The origin of the autoimmune disease-resistant LER rat: an outcross between the buffalo and autoimmune disease-prone Lewis inbred rat strains

The Lewis (LEW) rat strain is highly susceptible to a large number of experimentally induced inflammatory and autoimmune diseases. The Lewis resistant (LER) rat strain, which reportedly arose as a spontaneous mutation in a closed colony of LEW rats, is resistant to many of these disorders. The mechanism of resistance is not yet clear. We report the analysis of 19 simple dinucleotide repeat polymorphisms in 13 rat strains including the LEW/N and LER/N rat strains. The LEW/N and LER/N alleles were the same in only 42% of cases. For all of the other polymorphisms, the LER/N and Buffalo (BUF/N) rat strain alleles were identical. These data provide evidence that the LER strain did not arise as a spontaneous mutation in the LEW strain but is the result of an outcross between the LEW and BUF rat strains. The LER rat strain is now a recombinant inbred rat strain. This information should facilitate the genetic analysis of the loci responsible for resistance to experimental autoimmune disease in the LER rat.

Linkage map of 10 polymorphic markers on rat chromosome 2

Analysis of F2 intercross progeny of inbred F344/N x LEW/N rats led to the assignment of 10 polymorphic PCR-typable markers to rat chromosome 2. The markers form a single linkage group covering 47.9 cM with the following order: D2N1R-D2N28-FGG (gamma fibrinogen)-PKLR (liver and RBC pyruvate kinase)-ATP1A1 (the alpha-1 polypeptide of Na+/K+ transporting ATPase)-HSD3B (hydroxy-delta-5-steroid dehydrogenase)-D2N2R-D2N91-CAMKI (calmodulin-dependent protein kinase II)-D2N35. All but two of the markers (D2N1R and D2N2R) were detected using specific PCR primers flanking dinucleotide repeats. Sequences with dinucleotide repeats associated with five genes (FGG, PKLR, ATP1A1, HSD3B, and CAMKI) were identified in GenBank, and primers were designed to flank these repeats. The PCR primer pairs for three anonymous markers (D2N28, D2N91, and D2N35) were identified by sequencing cloned LEW/N rat genomic DNA containing (CA)n.(GT)n repeats. D2N1R and D2N2R were identified by PCR amplification of genomic DNA with single, nonspecific 10-base oligonucleotide primers. All of the markers were codominant except for D2N1R, D2N2R, and CAMKI, which only amplified from F344/N homozygous and heterozygous rat DNA. The seven codominant markers were highly polymorphic in 10 other inbred rat strains (SHR/N, WKY/N, MNR/N, MR/N, LOU/MN, BN/SsN, BUF/N, WBB1/N, WBB2/N, and ACI/N), suggesting that they will be useful for general mapping studies among these strains. Comparative gene mapping analysis indicated that a portion of the mapped region of rat chromosome 2 exhibits synteny conservation with regions of human chromosome 1 and mouse Chromosome 3.

Linkage map of seven polymorphic markers on rat chromosome 18

A genetic linkage map of seven polymorphic markers was created with F2 intercross progeny of F344/N and LEW/N rats and assigned to rat Chromosome (Chr) 18. Five of the markers described were defined by simple sequence length polymorphisms (SSLPs) associated with five genes: transthyretin (TTR), trypsin inhibitor-like protein (TILP), beta 2 adrenergic receptor (ADRB2), olfactory neuron-specific G protein (OLF), and gap junction protein (GJA1). One marker was defined by a restriction fragment length polymorphism (RFLP) detected with a probe for the human colony stimulating factor 1 receptor (CSF1R) gene. The D18N1R locus was defined by an anonymous DNA fragment amplified by the randomly amplified polymorphic DNA (RAPD) technique with a single short primer. These seven DNA loci formed a single genetic linkage group 30.4 cM in length with the following order: TTR-6.8 cM-D18N1R-9.1 cM-TILP-4.3 cM-CSF1R-0 cM-ADRB2-10.2 cM-OLF-0 cM-GJA1. The five SSLP markers were highly polymorphic. In a total of 13 inbred rat strains analyzed (F344/N, LEW/N, LOU/MN, WBB1/N, WBB2/N, MR/N, MNR/N, ACI/N, SHR/N, WKY/N, BN/SsN, BUF/N, and LER/N), three to six alleles were detected for each marker. Remarkable linkage conservation was detected between the region of rat Chr 18 mapped and a region of mouse Chr 18. However, genes associated with these markers have been mapped to three different human chromosomes (Chrs 5, 6, and 18). The markers described here should be useful for genetic mapping studies and genetic monitoring of inbred rat strains.

Map of seven polymorphic markers on rat chromosome 14: linkage conservation with human chromosome 4

Seven polymorphic markers identified by polymerase chain reaction (PCR) amplification, including markers for six genes--DRD1L (dopamine receptor, D1-like-2), GLUKA (glucokinase), PF4 (platelet factor 4), ALB (albumin), AFP (alpha-fetoprotein), and BSP (bone sialoprotein)--and one anonymous locus (D14N52), were mapped to a single 67-cM linkage group with F2 intercross progeny of F344/N and LEW/N inbred rat strains. Two of these markers, ALB and AFP, have previously been assigned to rat Chromosome (Chr) 14, allowing assignment of this entire linkage group. Five of the markers--DRD1L, PF4, ALB, AFP, and BSP--have been physically mapped to a large region of human Chr 4 encompassing the p arm and the q arm to band q28. Homologs of two of the markers, ALB and AFP, have been mapped to Chr 5 in the mouse. Comparison of human Chr 4 with the homologous regions on Chr 14 of the rat and Chr 5 of the mouse indicated that linkage conservation with human Chr 4 extends over a greater region in the rat than in the mouse. The markers described here were found to be highly polymorphic in twelve inbred strains (F344/N, LEW/N, ACI/N, BUF/N, BN/SsN, LOU/MN, MNR/N, MR/N, SHR/N, WBB1/N, WBB2/N, and WKY/N). These polymorphic markers should be useful in genetic linkage studies of important phenotypes in rats.

Genetic mapping of the athymic nude (RNU) locus in the rat to a region on chromosome 10

The nude trait in the rat is transmitted in an autosomal recessive manner and is associated with thymic aplasia, T-cell deficiency, and hairlessness. Congenic rats homozygous for the RNU (Rowett nude) locus are important models in the study of inflammatory disease, tumor growth, and transplant rejection. The RNU locus has not been previously mapped, and the nature of the gene product is unknown. To determine the map location of this gene, a single F344.rnu/rnu (athymic nude congenic Fischer rat) male congenic rat was bred with 3 LEW/N (NIH stock Lewis rat) female rats to produce F1 progeny. Twelve F1 brother-sister breeding pairs were established. Forty-nine phenotypically nude F2 offspring (198 total) were obtained. Linkage analysis done on F2 DNA revealed highly significant cosegregation between the nude phenotype and eight polymorphic markers located on Chromosome (Chr) 10. The tightest linkages were with: MYH3 (embryonic, skeletal myosin heavy chain) and SHBG (sex hormone-binding globulin), giving 2 point lod scores of 20.2, and 20.0, respectively. The map order and map distances, determined by multipoint linkage calculations, were: RR24-(16.1 cM)-MYH3-(3.5 cM)-SHBG-(4.7 cM)-RNU-(11.9 cM)-F16F2-(24.1 cM)-CLATP (citrate lyase ATPase)-(2.4 cM)-ACE (angiotensin converting enzyme)/PPY (pancreatic polypeptide)-(14.1 cM)-RR1023. The position of the RNU locus in the rat corresponds closely with that of the recently reported nu locus in the mouse. This finding suggests that the nude phenotype in the rat and the mouse arise from defects in homologous genes.

Local secretion of corticotropin-releasing hormone in the joints of Lewis rats with inflammatory arthritis

Corticotropin-releasing hormone (CRH), the principal regulator of the hypothalamic-pituitary-adrenal axis, is also secreted in peripheral inflammatory sites, where it acts as a local proinflammatory agent. Arthritis-susceptible LEW/N rats have profoundly deficient hypothalamic CRH responses to inflammatory stimuli and other stressors. Arthritis-resistant F344/N rats, on the other hand, have a robust increase in hypothalamic CRH in response to the same stimuli. Contrasting with these hypothalamic CRH responses, we now show that CRH expression is markedly increased in the joints and surrounding tissues of LEW/N rats with streptococcal cell wall- and adjuvant-induced arthritis, whereas it is not increased in similarly treated F344/N rats and is only transiently increased in congenitally athymic nude LEW.rnu/rnu rats. Glucocorticoid treatment suppressed, but did not eliminate, CRH immunoreactivity in the joints of LEW/N rats. CRH mRNA was present in inflamed synovia, as well as in spinal cord, and inflamed synovia also expressed specific CRH-binding sites. We compared CRH expression in inflamed joints with another well-characterized proinflammatory neuropeptide, substance P (SP), and found that SP immunoreactivity paralleled that of CRH. In summary, although LEW/N rats have deficient hypothalamic CRH responses to inflammatory stimuli compared with F344/N rats, they express relatively high levels of CRH at the site of inflammation. Analogous to SP, CRH may be delivered to the inflammatory site by peripheral nerves and/or synthesized at the inflammatory site. These data provide further support for the concept that CRH not only triggers the pituitary-adrenal antiinflammatory cascade, but also functions as an antithetically active local mediator of acute and chronic inflammatory arthritis. These data also illustrate the complex interrelationships of the nervous, endocrine, immune, and inflammatory systems.

Genetic map of nine polymorphic loci comprising a single linkage group on rat chromosome 10: Evidence for linkage conservation with human chromosome 17 and mouse chromosome 11

Seven genes and two anonymous markers were mapped to a single linkage group on rat chromosome 10 using progeny of an F2 intercross of Fischer (F344/N) and Lewis (LEW/N) inbred rats. Two genes, the neu oncogene or cellular homologue of the viral oncogene erbb2 (ERBB2) and growth hormone (GH) were mapped by Southern blot analysis of restriction fragment length polymorphisms. Five genes, embryonic skeletal myosin heavy chain (MYH3), androgen binding protein/sex hormone binding globulin (SHBG), asialoglycoprotein receptor (hepatic lectin)-1 (ASGR1), ATP citrate lysase (CLATP), and pancreatic polypeptide (PPY), and two anonymous markers, F16F2 and F10F1, were mapped using PCR amplification techniques. The PCR-typable polymorphic markers for the five genes were also highly polymorphic in 10 other inbred rat strains (SHR/N, WKY/N, MNR/N, MR/N, LOU/MN, BN/SsN, BUF/N, WBB1/N, WBB2/N, and ACI/N). These markers should be useful in genetic analysis of traits described in inbred rat strains, as well as in genetic monitoring of such strains. The loci in this linkage group covered 50 cM of rat chromosome 10 with the following order: MYH3, SHBG/ASGR1 (no recombinants detected), F16F2, ERBB2, CLATP, PPY, GH, and F10F1. Comparative gene mapping analysis indicated that this region of rat chromosome 10 exhibits linkage conservation with regions of human chromosome 17 and mouse chromosome 11.

The effect of norepinephrine on endotoxin-mediated macrophage activation

The effect of norepinephrine (NE) on the production of tumor necrosis factor (TNF) by rat spleen macrophages was determined. Following activation with lipopolysaccharide, analysis of both secreted and cell-associated samples showed that TNF activity was significantly suppressed in the presence of 10 microM NE. With the addition of the beta-receptor antagonist propranolol a partial reversal of the suppressive effect of NE was noted whereas the addition of the mixed alpha-receptor antagonist phentolamine induced a more pronounced suppressive effect in the supernatant fraction. Similar results were obtained with epinephrine and isoproterenol. Control experiments confirmed that this effect of NE was mediated at the level of macrophage activation. Analysis of lymphocyte activating factors demonstrated a similar pattern of response. Since factors released by macrophages participate in many aspects of the immune response, these results support a functional role for sympathetic innervation of the spleen in immune regulation.

Prazosin treatment during the effector stage of disease suppresses experimental autoimmune encephalomyelitis in the Lewis rat

As part of a study on the role of vasoactive amines in experimental autoimmune encephalomyelitis (EAE), we have found that treatment beginning 7 days post-inoculation (dpi) with the specific alpha 1-adrenoceptor antagonist prazosin can significantly suppress clinical signs of disease in the Lewis rat. In this paper we have addressed the effect of treatment with prazosin commencing at varying times in the disease process. The results show that treatment during the early inductive stage (1 to 6 dpi) has no effect on the clinical course of the disease, whereas treatment commencing at the time of onset of early clinical signs (10 to 16 dpi) still significantly suppresses EAE. Leakage of serum proteins into the central nervous system (CNS) and histologic expression of EAE are also suppressed. Prazosin had no effect on lymphocyte responses to mitogen or antigen as determined by lymphocyte transformation tests when lymphocytes were exposed to prazosin in vitro, and the responses of lymphocytes from prazosin-treated animals were similar to those from saline-treated animals. These results support the hypothesis that prazosin suppresses EAE through a direct vascular effect although they do not preclude an immunologic component to its mechanism of action.

Prazosin treatment during the effector stage of disease suppresses experimental autoimmune encephalomyelitis in the Lewis rat

As part of a study on the role of vasoactive amines in experimental autoimmune encephalomyelitis (EAE), we have found that treatment beginning 7 days post-inoculation (dpi) with the specific alpha 1-adrenoceptor antagonist prazosin can significantly suppress clinical signs of disease in the Lewis rat. In this paper we have addressed the effect of treatment with prazosin commencing at varying times in the disease process. The results show that treatment during the early inductive stage (1 to 6 dpi) has no effect on the clinical course of the disease, whereas treatment commencing at the time of onset of early clinical signs (10 to 16 dpi) still significantly suppresses EAE. Leakage of serum proteins into the central nervous system (CNS) and histologic expression of EAE are also suppressed. Prazosin had no effect on lymphocyte responses to mitogen or antigen as determined by lymphocyte transformation tests when lymphocytes were exposed to prazosin in vitro, and the responses of lymphocytes from prazosin-treated animals were similar to those from saline-treated animals. These results support the hypothesis that prazosin suppresses EAE through a direct vascular effect although they do not preclude an immunologic component to its mechanism of action.

Prazosin treatment suppresses increased vascular permeability in both acute and passively transferred experimental autoimmune encephalomyelitis in the Lewis rat

Prazosin, an antagonist of the alpha 1-adrenoceptor, has been found to suppress the clinical and histologic expression of experimental autoimmune encephalomyelitis (EAE) in the Lewis rat. This effect appears to be specific for the alpha 1-receptor. To determine the effect of this drug on vascular permeability to serum proteins and inflammatory cells, leakage of serum proteins into the central nervous system (CNS) was measured with [125I]albumin, and quantitation of cellular inflammation was determined by an estimation of total DNA. The results show that in both actively induced and passively transferred models of the disease, treatment with prazosin significantly suppresses leakage of serum proteins into the CNS but does not significantly suppress the increase of DNA. The results of the [125I]albumin studies additionally support the conclusion that the extent of vascular permeability to serum proteins in the spinal cord is a significant correlate of clinical disease. The results of the DNA estimation were at variance with the histologic evidence of cellular infiltration. We conclude that treatment with prazosin has a significant effect on the development of vascular edema in EAE. These results additionally validate a role for the adrenergic receptor in the development of EAE, and support the hypothesis that the primary site of action of prazosin is on the vascular alpha 1-adrenoceptor.

Prazosin treatment suppresses increased vascular permeability in both acute and passively transferred experimental autoimmune encephalomyelitis in the Lewis rat

Prazosin, an antagonist of the alpha 1-adrenoceptor, has been found to suppress the clinical and histologic expression of experimental autoimmune encephalomyelitis (EAE) in the Lewis rat. This effect appears to be specific for the alpha 1-receptor. To determine the effect of this drug on vascular permeability to serum proteins and inflammatory cells, leakage of serum proteins into the central nervous system (CNS) was measured with [125I]albumin, and quantitation of cellular inflammation was determined by an estimation of total DNA. The results show that in both actively induced and passively transferred models of the disease, treatment with prazosin significantly suppresses leakage of serum proteins into the CNS but does not significantly suppress the increase of DNA. The results of the [125I]albumin studies additionally support the conclusion that the extent of vascular permeability to serum proteins in the spinal cord is a significant correlate of clinical disease. The results of the DNA estimation were at variance with the histologic evidence of cellular infiltration. We conclude that treatment with prazosin has a significant effect on the development of vascular edema in EAE. These results additionally validate a role for the adrenergic receptor in the development of EAE, and support the hypothesis that the primary site of action of prazosin is on the vascular alpha 1-adrenoceptor.

Astrocytic reactivity and intermediate filament metabolism in experimental autoimmune encephalomyelitis: the effect of suppression with prazosin

In either actively or passively transferred experimental autoimmune encephalomyelitis (EAE), increased immunocytochemical staining of glial fibrillary acidic protein (GFAP) in astrocytes was detected early in the disease process in both the gray and white matter of the spinal cord. Staining was not restricted to areas of perivascular mononuclear infiltration, and was observed at all levels of the cord. This enhanced staining pattern was delayed in rats in which clinical signs of EAE had been suppressed by treatment with the alpha 1-adrenoceptor antagonist prazosin. This glial reaction in EAE was not accompanied by increased GFAP synthesis, as measured by in vitro labeling of spinal cord slices, nor an increase in GFAP content, as measured by densitometry of intermediate filament fractions separated by polyacrylamide gel electrophoresis. Total protein synthesis was increased, with vimentin being labeled especially heavily; in prazosin-treated EAE animals, the increase in total protein synthesis was reduced and delayed.