RESUMO
We present the first joint analysis of cluster abundances and auto or cross-correlations of three cosmic tracer fields: galaxy density, weak gravitational lensing shear, and cluster density split by optical richness. From a joint analysis (4×2pt+N) of cluster abundances, three cluster cross-correlations, and the auto correlations of the galaxy density measured from the first year data of the Dark Energy Survey, we obtain Ω_{m}=0.305_{-0.038}^{+0.055} and σ_{8}=0.783_{-0.054}^{+0.064}. This result is consistent with constraints from the DES-Y1 galaxy clustering and weak lensing two-point correlation functions for the flat νΛCDM model. Consequently, we combine cluster abundances and all two-point correlations from across all three cosmic tracer fields (6×2pt+N) and find improved constraints on cosmological parameters as well as on the cluster observable-mass scaling relation. This analysis is an important advance in both optical cluster cosmology and multiprobe analyses of upcoming wide imaging surveys.
RESUMO
We report the first detection of gravitational lensing due to galaxy clusters using only the polarization of the cosmic microwave background (CMB). The lensing signal is obtained using a new estimator that extracts the lensing dipole signature from stacked images formed by rotating the cluster-centered Stokes QU map cutouts along the direction of the locally measured background CMB polarization gradient. Using data from the SPTpol 500 deg^{2} survey at the locations of roughly 18 000 clusters with richness λ≥10 from the Dark Energy Survey (DES) Year-3 full galaxy cluster catalog, we detect lensing at 4.8σ. The mean stacked mass of the selected sample is found to be (1.43±0.40)×10^{14}M_{â} which is in good agreement with optical weak lensing based estimates using DES data and CMB-lensing based estimates using SPTpol temperature data. This measurement is a key first step for cluster cosmology with future low-noise CMB surveys, like CMB-S4, for which CMB polarization will be the primary channel for cluster lensing measurements.
RESUMO
Olfactory receptors are difficult to functionally express in heterologous cells. They are typically retained in the endoplasmic reticulum of cells commonly used for functional expression studies and are only released to the plasma membrane in mature cells of the olfactory receptor neuron lineage. A recently developed olfactory cell line, odora, traffics olfactory receptors to the plasma membrane when differentiated. We found that undifferentiated odora cells do not traffic olfactory receptors to their surface, even though they release the receptors to the Golgi apparatus and endosomes. This behavior differs from other cell lines tested thus far. Differentiated odora cells also properly traffic vomeronasal receptors of the VN1 type, which lack sequence similarity to olfactory receptors. ODR-4, a protein that is necessary for plasma membrane trafficking of a chemosensory receptor in nematodes, facilitates trafficking of rat olfactory receptor U131 in odora and Chinese hamster ovary cells. Olfactory receptor trafficking from the endoplasmic reticulum to the plasma membrane involves at least two steps whose regulation depends on the maturation state of cells in the olfactory receptor neuron lineage. These results also indicate that some components of the regulatory mechanism are conserved.
Assuntos
Proteínas de Caenorhabditis elegans , Neurônios Receptores Olfatórios/metabolismo , Receptores Odorantes/metabolismo , Animais , Células CHO , Diferenciação Celular , Linhagem Celular , Membrana Celular/metabolismo , Cricetinae , Retículo Endoplasmático/metabolismo , Endossomos/metabolismo , Complexo de Golgi/metabolismo , Imuno-Histoquímica , Microscopia Confocal , Modelos Biológicos , Transporte Proteico , Ratos , Receptores Odorantes/fisiologia , Proteínas Recombinantes/metabolismo , TransfecçãoRESUMO
Immunocytochemistry using antisera specific for the G-protein alpha subunits G(alphai), G(alphaq), and G(alphas) revealed similar patterns of immunoreactivity in the lobster brain. Immunoreactivity was strongest in neuropil, especially the olfactory and accessory lobes, and was characterized by bundles of fine threads leading to dense concentrations of punctate staining in the glomeruli. This may reflect the concentration of G-protein alpha subunits at synapses. The major differences between the antisera were distinct patterns of staining intensity in subregions of glomeruli of the olfactory and accessory lobes. This result is potentially correlated with previous evidence that these subregions are neurochemically distinct. Neuronal cell bodies contained moderate levels of immunoreactivity at the plasma membrane and faint staining in the cytoplasm. The olfactory globular tract was moderately immunoreactive, but other fiber tracts were weakly immunoreactive. Immunoreactivity in the deutocerebral commissure consisted of small oval cell bodies and strands that formed a reticulated pattern, suggestive of glia. Photoaffinity labelling by using an analog of GTP demonstrated that histamine activated G(alphai) in brain homogenates. Further evidence of G-protein activation was obtained by showing that stimulation with a mixture of neuroactive substances increased the amount of phospholipase C-beta associated with membranes, G(alphaq), and G(beta). The lobster brain, especially in its neuropil regions, is richly endowed with neuromodulatory biochemical pathways involving G(alphai), G(alphaq), and G(alphas).
Assuntos
Encéfalo/metabolismo , Proteínas de Ligação ao GTP/metabolismo , Proteínas de Ligação ao GTP/fisiologia , Nephropidae/fisiologia , Neurotransmissores/fisiologia , Animais , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP , Isoenzimas/metabolismo , Nephropidae/metabolismo , Fosfolipase C beta , Isoformas de Proteínas/metabolismo , Distribuição Tecidual , Fosfolipases Tipo C/metabolismoRESUMO
A cDNA encoding an ionotropic gamma-aminobutyric acid (GABA) receptor subunit was isolated from a lobster (Homarus americanus) cDNA library. A longer version of this cDNA, containing a 108-bp insert, was also detected. The two cDNAs are predicted to encode alternatively spliced proteins of 485 and 521 amino acids, respectively. The sequences were most similar to the Drosophila RDL (resistance to dieldrin) GABA subunit with 54% identity, and 30-35% identity with vertebrate ionotropic GABA receptor subunits. Only the shorter clone formed functional ion channels when transfected into human embryonic kidney (HEK) 293 cells. GABA caused a Cl(-)-selective current in the presence of GABA that was blocked by picrotoxin. The GABA-induced current was weakly sensitive to the GABA(A) antagonist, bicuculline, but was enhanced by pentobarbital. Expression of the GABA receptor mRNA was highest in brain and the olfactory organ, but was not detected in leg muscle. These data suggest that the isolated cDNAs are likely to encode proteins that comprise subunits of native GABA receptors expressed in olfactory receptor neurons and projection neurons of the olfactory deutocerebrum.
Assuntos
Sequência de Aminoácidos/genética , DNA Complementar/genética , RNA Mensageiro/metabolismo , Receptores de GABA-A/genética , Olfato/genética , Processamento Alternativo , Animais , Linhagem Celular , DNA Complementar/metabolismo , Drosophila , Humanos , Ativação do Canal Iônico , Rim/citologia , Rim/metabolismo , Dados de Sequência Molecular , Nephropidae , Receptores de GABA-A/efeitos dos fármacos , Receptores de GABA-A/metabolismo , Ácido gama-Aminobutírico/farmacologiaRESUMO
A cDNA clone (lobGRK2) encoding a protein of 690 amino acids with significant similarity to the GRK2 subfamily of G-protein coupled receptor kinases was isolated. lobGRK2 was widely expressed as a 9-kb major transcript and a protein of 80 kDa. It was most abundant in the brain and the olfactory organ but was absent in the eye/eyestalk. Immunocytochemistry revealed lobGRK2 immunoreactivity in the outer dendritic segments of the olfactory receptor neurons, the site of olfactory transduction. LobGRK2 immunoreactivity was observed in most neuronal structures in the brain, although with varying intensity. It was strongest in neuropil, especially the olfactory and accessory lobes but was also detectable in neuronal cell bodies. Stimulation of brain homogenates with a mixture of neurotransmitters increased the association of lobGRK2 with membranes and with G(beta). Similarly, stimulation of olfactory dendrite homogenates with an odorant mixture caused lobGRK2 to associate with G(beta). These results support the conclusion that lobGRK2 responds to odorants and to neurotransmitters and may act to initiate desensitization by phosphorylating G-protein-coupled receptors in the olfactory organ and the brain, respectively.
Assuntos
Membrana Celular/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/genética , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Proteínas Heterotriméricas de Ligação ao GTP/metabolismo , Nephropidae/metabolismo , Animais , Proteínas de Membrana/metabolismo , Dados de Sequência Molecular , Condutos Olfatórios/metabolismo , Neurônios Receptores Olfatórios/metabolismo , Receptores Odorantes/metabolismo , Homologia de Sequência de Aminoácidos , Transdução de Sinais , Quinases de Receptores Adrenérgicos betaRESUMO
A cDNA clone encoding a protein of 1116 amino acids with significant homology to beta-isoforms of phospholipase C was isolated from lobster olfactory organ cDNA libraries and named lobPLCbeta. This cDNA hybridized predominantly to a 9 kb transcript in RNA from olfactory organ, pereiopod, brain, and eye-eyestalk and to several smaller minor transcripts only in eye-eyestalk. An antiserum raised to the C terminus of lobPLCbeta detected immunoreactivity in a single 130 kDa band in olfactory aesthetasc hairs, olfactory organ, pereiopod, dactyl, and brain. In eye-eyestalk this 130 kDa band was abundant, and minor bands of 100, 79, and 57 kDa also were detected. In cross sections of the aesthetasc hairs, immunoreactivity was detected in the outer dendritic segments of the olfactory receptor neurons, the site of olfactory transduction. A complex odorant caused lobPLCbeta immunoreactivity to increase in membrane fractions and decrease in soluble fractions of homogenates of aesthetasc hairs. The odorant also increased the amount of lobPLCbeta in immunoprecipitates of Galphaq and Gbeta from homogenates of aesthetasc hairs. These results support the conclusion that lobPLCbeta mediates olfactory transduction.
Assuntos
Subunidades beta da Proteína de Ligação ao GTP , Subunidades gama da Proteína de Ligação ao GTP , Proteínas de Ligação ao GTP/metabolismo , Proteínas Heterotriméricas de Ligação ao GTP , Isoenzimas/genética , Isoenzimas/metabolismo , Neurônios Receptores Olfatórios/enzimologia , Olfato/fisiologia , Fosfolipases Tipo C/genética , Fosfolipases Tipo C/metabolismo , Estruturas Animais/enzimologia , Animais , Clonagem Molecular , DNA Complementar , Dendritos/enzimologia , Proteínas do Olho/análise , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP , Regulação Enzimológica da Expressão Gênica , Inositol 1,4,5-Trifosfato/metabolismo , Dados de Sequência Molecular , Nephropidae , Odorantes , Neurônios Receptores Olfatórios/ultraestrutura , Fosfolipase C beta , RNA Mensageiro/genética , Homologia de Sequência de Aminoácidos , Transdução de Sinais/fisiologiaRESUMO
Olfactory receptors are difficult to express functionally in heterologous cells. We found that olfactory receptors traffic poorly to the plasma membrane even in cells with neuronal phenotypes, including cell lines derived from the olfactory epithelium. Other than mature olfactory receptor neurons, few cells appear able to traffic olfactory receptors to the plasma membrane. In human embryonic kidney 293 cells and Xenopus fibroblasts, olfactory receptor immunoreactivity overlapped with a marker for the endoplasmic reticulum (ER) but not with markers for the Golgi apparatus or endosomes. Except for the ER, olfactory receptors were therefore absent from organelles normally involved in the plasma membrane trafficking of receptors. Olfactory receptors truncated prior to transmembrane domain VI were expressed in the plasma membrane, however. Co-expression of the missing C-terminal fragment with these truncated receptors prevented their expression in the plasma membrane. Intramolecular interactions between N- and C-terminal domains joined by the third cytoplasmic loop appear to be responsible for retention of olfactory receptors in the ER of heterologous cells. Our results are consistent with misfolding of the receptors but could also be explained by altered trafficking of the receptors.
Assuntos
Retículo Endoplasmático/metabolismo , Neurônios/metabolismo , Receptores Odorantes/biossíntese , Receptores Odorantes/genética , Animais , Células CHO , Linhagem Celular , Membrana Celular/metabolismo , Cricetinae , Fibroblastos/fisiologia , Humanos , Rim , Neuroblastoma , Proteínas Recombinantes/biossíntese , Transfecção , Células Tumorais Cultivadas , XenopusRESUMO
BACKGROUND: This is the first long-term follow-up of patients discharged from a medium secure unit. AIMS: To describe the short- and long-term outcomes of admission for all patients discharged during a 14-year period. METHOD: A longitudinal cohort study of all 234 patients discharged from the Denis Hill Unit, Bethlem Royal Hospital, between 1980 and 1994, followed for an average 6.6 years. RESULTS: Although 48% of admissions were from prison, only 8% returned there, with most being transferred to another psychiatric bed. One-fifth of patients spent none of the follow-up time in the community; 75% of patients had at least one readmission; only 24% were convicted of further offences. CONCLUSIONS: Re-offending rates are comparable with those for patients discharged from high-security hospitals, and much lower than those for released prisoners. The high readmission rates indicate the need for a range of services to maintain former patients in the community.
Assuntos
Internação Compulsória de Doente Mental/estatística & dados numéricos , Hospitais Psiquiátricos/estatística & dados numéricos , Adolescente , Adulto , Idoso , Estudos de Coortes , Inglaterra , Feminino , Seguimentos , Hospitalização , Hospitais Psiquiátricos/organização & administração , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Avaliação de Processos e Resultados em Cuidados de Saúde , Admissão do Paciente , Prognóstico , Fatores de TempoRESUMO
BACKGROUND: A follow-up of patients discharged from medium secure psychiatric units is used to compare outcome in patients of different ethnic origin. AIMS: To test the hypothesis that there are systematic differences in clinical outcome between ethnic groups. METHOD: A descriptive, longitudinal cohort study of discharges from a medium secure unit is used to compare the 125 patients of White/European ethnic origin and the 104 patients of Black/African-Caribbean origin. RESULTS: Patients of African-Caribbean origin were admitted at three times the rate of White patients, had a higher prevalence of psychosis and a lower prevalence of personality disorder. There was no difference in outcome as measured by location at follow-up, readmission or re-offending. CONCLUSIONS: The higher rate of admission of African-Caribbean patients is consistent with a higher level of demand. There is a need for studies of the pathways by which patients from ethnic minorities reach medium-security accommodation, with a view to early intervention.
Assuntos
Internação Compulsória de Doente Mental/estatística & dados numéricos , Hospitais Psiquiátricos/estatística & dados numéricos , Transtornos Mentais/etnologia , Adulto , África/etnologia , Estudos de Coortes , Inglaterra/epidemiologia , Feminino , Seguimentos , Hospitalização , Hospitais Psiquiátricos/organização & administração , Humanos , Estudos Longitudinais , Masculino , Avaliação de Processos e Resultados em Cuidados de Saúde , Prognóstico , Índias Ocidentais/etnologiaRESUMO
We have isolated from the olfactory organ of the American lobster (Homarus americanus) two cDNA clones with homology to beta subunits of G proteins. LobGbeta1 contained a complete open reading frame that predicted an amino acid sequence with >80% identity to Gbeta sequences from other species. LobGbeta2 was a fragment of an open reading frame whose predicted amino acid sequence had 65-69% identity to other Gbeta sequences. LobGbeta2 mRNA was not detectable in the brain, eye plus eyestalk, leg, dactyl, olfactory organ, or tail muscle. In contrast, lobGbeta1 was expressed in all these tissues as a single mRNA species of 6.4 kb and a protein of 37 kD. In the brain and olfactory organ, Gbeta immunoreactivity was almost exclusively confined to neurites: the neuropil regions of the brain and the outer dendrites of the olfactory receptor neurons. Coimmunoprecipitation revealed that lobster Gbeta interacted with both Galpha s and Galpha q. LobGbeta1 is likely to be involved in a wide range of signaling events including olfactory transduction and synaptic transmission in the brain.
Assuntos
Química Encefálica/fisiologia , Encéfalo/citologia , Dendritos/metabolismo , Proteínas de Ligação ao GTP/biossíntese , Nephropidae/metabolismo , Neurópilo/metabolismo , Neurônios Receptores Olfatórios/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Química Encefálica/genética , Clonagem Molecular , DNA Recombinante/biossíntese , DNA Recombinante/genética , Immunoblotting , Imuno-Histoquímica , Dados de Sequência Molecular , Neurópilo/citologia , Fases de Leitura Aberta , Órgãos dos Sentidos/fisiologiaRESUMO
The efficiency of translational initiation depends upon the sequence context surrounding the AUG codon (1, 2, 3). A purine at position -3 contributes critically to context, but other neighboring nucleotides are also important. Nucleotide frequencies at these neighboring positions vary among distant taxa (4, 5). We have analyzed the translational initiation sites of cnidarian, echinoderm, molluscan, annelid, and crustacean sequences in nucleotide sequence databases. These taxa conform to the pattern of a strong preference for a purine at -3, but the frequencies of nucleotides at neighboring positions are characteristic for each taxon. The consensus translational initiation sequences of the marine invertebrate taxa are also different from those of vertebrates and single-celled eukaryotes. These consensus sequences are useful guides for predicting translational initiation sites in cDNA clones.
Assuntos
Sequência Consenso , Invertebrados/genética , Biossíntese de Proteínas , Animais , Anelídeos/genética , Composição de Bases , Sequência de Bases , Cnidários/genética , Códon , DNA Complementar/química , Equinodermos/genética , Moluscos/genéticaRESUMO
Replacing the G-protein-coupling domains of the beta 2-adrenergic receptor with homologous domains of putative olfactory receptors produced chimeric receptors which were able to stimulate pigment dispersion in Xenopus melanophores, a G-protein-mediated pathway. A multiple replacement chimera containing the second, third and C-terminal cytoplasmic domains of receptor OR5 elevated cyclic adenosine 3':5'-monophosphate (cAMP) and suppressed production of inositol phosphates. Co-expression of G alpha olf did not alter the strength of response of this chimera. A novel rat olfactory receptor cDNA (U131) was isolated and sequenced. Expression of U131 and OR5 constructs containing an N-terminal epitope-tag or C-terminal fusion to green fluorescent protein occurred in an intracellular network but not in the plasma membrane of heterologous cells. Similarly treated beta 2-adrenergic receptors were functional and were observed in the plasma membrane and the intracellular network. These results demonstrate that the putative cytoplasmic domains of olfactory receptors are capable of functional interaction with heterologous G-proteins of the G alpha s subtype. Instead, the absence of these receptors from the plasma membrane of heterologous cells appears to explain our inability to determine if odorants can activate the olfactory receptor clones. We hypothesize that the olfactory receptors have requirements for maturation and targeting to the plasma membrane that are different from most other G-protein-coupled receptors.
Assuntos
Receptores Adrenérgicos/biossíntese , Receptores Odorantes/biossíntese , Proteínas Recombinantes de Fusão/biossíntese , Adenilil Ciclases/metabolismo , Sequência de Aminoácidos , Animais , Células Cultivadas , Clonagem Molecular , DNA Complementar/isolamento & purificação , Ativação Enzimática , Melanóforos/metabolismo , Dados de Sequência Molecular , RatosRESUMO
We have isolated from an American lobster (Homarus americanus) olfactory organ cDNA library a clone, hG alpha(q), with >80% identity to mammalian and arthropod G alpha(q) sequences. In brain and olfactory organ, hG alpha(q) mRNA was expressed predominantly in neurons, including virtually all the neuronal cell body clusters of the brain. G alpha(q) protein was also expressed broadly, appearing on western blots as a single band of 46 kDa in brain, eyestalk, pereiopod, dactyl, tail muscle, olfactory organ, and aesthetasc hairs. These results suggest that hG alpha(q) plays a role in a wide variety of signal transduction events. Its presence in the olfactory aesthetasc hairs, which are almost pure preparations of the outer dendrites of the olfactory receptor neurons, the expression of a single hG alpha(q) mRNA species (6 kb) in the olfactory organ, and the localization of hG alpha(q) mRNA predominantly in the olfactory receptor neurons of the olfactory organ strongly suggest that one function of hG alpha(q) is to mediate olfactory transduction.
Assuntos
Proteínas de Ligação ao GTP/genética , Nephropidae/genética , Neurônios Receptores Olfatórios/química , Animais , Especificidade de Anticorpos , Northern Blotting , Western Blotting , Química Encefálica/fisiologia , Clonagem Molecular , DNA Complementar , Proteínas de Ligação ao GTP/análise , Proteínas de Ligação ao GTP/imunologia , Gânglios dos Invertebrados/química , Gânglios dos Invertebrados/citologia , Expressão Gênica/fisiologia , Hibridização In Situ , Mecanorreceptores/química , Dados de Sequência Molecular , Sistema Nervoso/química , Sistema Nervoso/citologia , RNA Mensageiro/análise , Homologia de Sequência de Aminoácidos , Transdução de Sinais/fisiologia , Olfato/fisiologiaAssuntos
Crime , Política Pública , Governo , Humanos , Transtornos Mentais/terapia , Serviços de Saúde Mental , Prisões , Reino UnidoRESUMO
We have isolated from an American lobster (Homarus americanus) olfactory organ cDNA library a clone, lobG alphaS, with >70% identity to mammalian and arthropod G alphaS sequences. In genomic Southern blots, a fragment of lobG alphaS detected only one band, suggesting the lobsters have a single G alphaS gene. In brain and olfactory organ, lobG alphaS mRNA was expressed predominantly in neurons, including many of the neuronal cell body clusters of the brain. G alphaS protein was also expressed broadly, appearing on western blots as a band of 51.8 kDa in brain, eyestalk, pereiopod, dactyl, tail muscle, olfactory organ, and aesthetasc hairs. These results suggest that lobG alphaS plays a role in a wide variety of signal transduction events. Its presence in the olfactory aesthetasc hairs, which are almost pure preparations of the outer dendrites of the olfactory receptor neurons, and the expression of lobG alphaS mRNA in the olfactory receptor neurons of the olfactory organ indicate that lobG alphaS may mediate olfactory transduction. That virtually all ORNs express lobG alphaS mRNA equally predicts that hyperpolarizing odor responses mediated by cyclic AMP are a property of all lobster olfactory receptor neurons.
Assuntos
Encéfalo/metabolismo , Subunidades alfa Gs de Proteínas de Ligação ao GTP/biossíntese , Neurônios/metabolismo , Condutos Olfatórios/metabolismo , Sequência de Aminoácidos , Animais , Artrópodes , Clonagem Molecular , DNA Complementar , Subunidades alfa Gs de Proteínas de Ligação ao GTP/química , Biblioteca Gênica , Hibridização In Situ , Mamíferos , Dados de Sequência Molecular , Nephropidae , Especificidade de Órgãos , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Alinhamento de Sequência , Homologia de Sequência de AminoácidosRESUMO
Analysis of functional aspects of the molecular structure of proteins often requires a means to selectively alter structure and subsequently analyze function. We have adapted a method of overlap extension polymerase chain reaction (PCR) to generate multiple domain replacements in G-protein coupled receptors. The examples described herein are beta 2-adrenergic receptors whose G-protein coupling domains have been replaced by homologous domains of olfactory receptors, but the procedure has also been used to produce constructs with mutations, deletions, and fusions of two complete open reading frames. The chimeric olfactory-adrenergic receptors were assayed by functional expression in clonal lines of Xenopus melanophores. The ability of G-protein coupled second messenger pathways to cause translocation of pigment organelles within melanophores allows the use of video microscopy to assay the function of the chimeric receptors. Digital automation of microscope stage, camera, and image processing allows multiple parallel experiments to be performed. Melanophores allow responses mediated by the Gs, Gq and Gi pathways to be assayed with equal efficiency and the specificity of the coupling between chimera (or receptor) and G-protein subtypes can be rapidly determined.
Assuntos
Melanóforos/citologia , Reação em Cadeia da Polimerase/métodos , Receptores Adrenérgicos beta 2/biossíntese , Receptores Odorantes/biossíntese , Animais , Técnicas de Cultura de Células/métodos , Células Clonais , Primers do DNA , DNA Recombinante , Proteínas de Ligação ao GTP/metabolismo , Indicadores e Reagentes , Melanóforos/fisiologia , Receptores Adrenérgicos beta 2/análise , Receptores Odorantes/análise , Proteínas Recombinantes de Fusão/análise , Proteínas Recombinantes de Fusão/biossíntese , Transfecção/métodos , XenopusRESUMO
Melanophore pigment dispersion is a sensitive bioassay for activation of the adenylyl cyclase and phospholipase C second-messenger pathways. The necessity of protein kinase activation in causing pigment dispersion was confirmed for eight agonists of endogenous melanophore receptors and for two transfected receptors. All agonists and receptors previously shown to elevate intracellular cAMP in melanophores--melanocyte stimulating hormone, light, (-) norepinephrine, 5-hydroxytrptamine, and the beta2-adrenergic receptor--were able to stimulate pigment dispersion in the presence of Ro31-8220, a potent inhibitor of protein kinase C, but were blocked in the presence of H89, an inhibitor of cAMP-dependent protein kinase. The bombesin receptor, which elevates intracellular IP3 in melanophores, was unable to stimulate pigment dispersion in the presence of Ro31-8220 or H89. Agonists whose mechanism of activation of pigment dispersion are unknown were also tested. Endothelin 3 responses were blocked by both H89 and Ro31-8220, predicting coupling to phospholipase C. Vasoactive intestinal polypeptide, oxytocin, and calcitonin gene-related peptide beta responses were blocked only by H89, predicting coupling to adenylyl cyclase.