Coral diversity and disease in Mexico.

Field studies and empirical tests of the 'diversity-disease hypothesis' demonstrate the effects of species richness on disease transmission and severity in plant systems. Yet the converse, i.e. effects of disease on diversity, is rarely considered in either relatively well-studied plant systems or marine ecosystems. We investigated these effects along the Mexican Yucatan Peninsula to (1) quantify the relationship between disease prevalence and coral diversity, (2) test the hypothesis that octocoral and scleractinian disease prevalence are associated with one another, and (3) establish a long-term dataset. Aspergillosis of sea fans and 6 scleractinian diseases were documented. Prevalence of aspergillosis declined from 12.85% in 2002 to 5.26% in 2004, while prevalence of scleractinian diseases remained relatively constant at 5.7 +/- 0.8% in 2002 and 7.96 +/- 0.7% in 2004. Sites were relatively rich (71 species of octocoral and scleractinian corals) and even (E5 > 0.5). Sea fan disease prevalence was not associated with scleractinian disease prevalence, nor were there consistent associations between disease and measures of diversity. However, the most abundant octocoral and scleractinian species are susceptible to infection with several diseases, and disease may alter coral diversity in complex ways. These data represent the first in what will become a long-term dataset monitoring disease prevalence and associated changes in coral diversity.

Histology of a human biopsy section following the placement of a subepithelial connective tissue graft.

This case report histologically examines the type of attachment that can occur after root coverage of a long-standing facial recession defect on a maxillary premolar with a subepithelial connective tissue graft. Histologic findings suggest that various types of tissue attachment, including periodontal regeneration, may occur over a recession defect after placement of a subepithelial connective tissue graft. In the present case, it was noteworthy that after 1 year the greatest area of exposed root surface was covered by a connective tissue attachment (adhesion), which had remained intact during orthodontic movement and distal drifting of the tooth.

Patch-size dependent habitat modification and facilitation on New England cobble beaches by Spartina alterniflora.

Most marine habitats are generated by the presence of habitat-modifying species. However, little is know about many aspects of this process, such as how individual- and population-level traits of habitat modifiers affect their ability to reduce environmental stress and thus facilitate other species. An important habitat modifier in New England is the intertidal grass Spartina alterniflora which facilitates the establishment and persistence of cobble beach plant communities by reducing wave-related disturbance. The objectives of this study were to (1) quantify the modification of cobble beach habitats by S. alterniflora, (2) determine how this process is related to S. alterniflora bed traits, and (3) determine why small patches of S. alterniflora generally remain unoccupied by cobble beach plants. Our results demonstrate that S. alterniflora substantially reduces flow-related physical disturbance on cobble beaches. Behind S. alterniflora, mean flow velocity was reduced by 40-60% and substrate stability was dramatically increased compared to portions of the shoreline not bordered by this species. These comparative results were supported by a S. alterniflora shoot removal experiment, which resulted in a 33% increase in average flow velocity and an 85% increase in substrate instability relative to control areas. There was a strong inverse logarithmic relationship between bed length and both average flow velocity and substrate instability behind S. alterniflora. Most S. alterniflora beds were small and bed length was significantly related to the presence of one or more cobble beach plant species. Only 13% of beds <25 m and 40% of beds 30-40 m in length were occupied, in contrast to an occupancy rate of 87% for beds >40 m long. Seeds of two annual cobble beach species (Suaeda linearis and Salicornia europaea) were added to plots behind large (>100 m in length) and small S. alterniflora (<25 m) beds with and without a substrate stabilization manipulation. Seedlings of both species only emerged and established behind small beds when the substrate was stabilized. These results indicate that smaller S. alterniflora patches are usually unoccupied because they do not stabilize the substrate to a degree that meets the establishment requirements of seedlings. Thus, both habitat modification and facilitation by S. alterniflora are patch-size dependent. The conditionality of this facilitation appears to generate a pattern of patchy yet predictable population and community distribution at a landscape spatial scale.

Characterization of the promoter region of the human somatostatin receptor subtype 2 gene and localization of sequences required for estrogen-responsiveness.

Somatostatin receptor (sst) subtype 2 mRNA is potently regulated by 17beta-estradiol (E2) in a time and dose-dependent manner in the estrogen receptor (+) human breast cancer cell line T47D. To explore the mechanism involved in E2 regulated expression of sst2, we isolated and characterized a genomic clone containing over 5.3 kilobase pairs (kb) of the 5' flanking region of the human sst2 gene. The 5'-flanking region lacks both TATA and CCAAT boxes. Primer extension and RNAase protection analysis revealed the existence of two transcriptional start sites, located within an initiator-like sequence, 85 and 82 bp upstream of the translational initiation methionine. The 5.3-kb 5'-flanking region was an active promoter in T47D cells but was inactive in MDA MB 435s cells, a human breast cancer cell line that does not express sst2. Deletion analysis identified both positive and negative regulatory elements within the 5.3-kb fragment. Furthermore, transcriptional regulation by E2 was mediated by a distal 1.5-kb fragment located 3.8 kb from the transcriptional start sites. Determining the precise ERE will provide important insights into the complex regulation of sst2 expression in normal and neoplastic tissue.

Estrogen regulates somatostatin receptor subtype 2 messenger ribonucleic acid expression in human breast cancer cells.

Somatostatin (SRIF) and its analogs exhibit antiproliferative effects that are mediated by SRIF receptors (sst) present in responsive normal and neoplastic tissue including breast cancer. However, information regarding regulation of sst gene expression in cancer cells and modulation of SRIF binding is limited. In the present study we have determined the pattern of sst subtype messenger RNA (mRNA) expression in human breast cancer cells. Furthermore, we investigated the effect of 17beta-Estradiol (E2) treatment on steady state levels of sst mRNA by solution hybridization/nuclease protection analysis and on SRIF binding to membranes of treated cells by receptor binding assay. sst2 mRNA was highly expressed in T47D, ZR75-1, and MDA MB231 cells. Transcripts for sst1 were also detected at very low levels in ZR75-1 cells, whereas sst5 mRNA was expressed at low levels in MCF-7 cells. No sst subtype was detected in MDA MB 435s cells. When the estrogen receptor (ER)(+) cell lines T47D and ZR75-1 were cultured in phenol red-free media plus CS-FCS, sst2 mRNA levels decreased by 60-80% compared with complete serum controls. Adding E2 restored sst2 mRNA levels to control in both cell lines. Moreover, the effect of E2 on sst2 gene expression in T47D and ZR75-1 cells was dose- and time-dependent. In contrast, neither culturing in phenol red-free media plus CS-FCS nor E2 influenced sst2 expression in the ER(-) cell line MDA MB231. E2-induced regulation of SRIF binding and sst2 mRNA expression occurred in a parallel manner in T47D cells but were dissociated in ZR75-1 cells. The pure antiestrogen ICI 182 780 inhibited E2-induced sst2 expression in both cell lines. The antiestrogen 4OH tamoxifen showed strong estrogen-like effects on sst2 mRNA expression in T47D cells, while acting as a potent antiestrogen in ZR75-1 cells. Thus, these data suggest that E2 regulates sst2 expression in human breast cancer cell lines through the ER. The human breast cancer cell lines provide a useful model to examine the molecular mechanisms involved in E2 regulation of sst2 expression.

The subepithelial connective tissue graft palatal donor site: anatomic considerations for surgeons.

Surgeons must become completely familiar with the anatomy of the palatal donor site to feel confident in providing the subepithelial connective tissue graft procedure. Variations in the size and shape of the hard palate affect the dimensions of donor tissue harvested, as well as the location of the greater palatine neurovascular bundle. This article classifies palatal vaults according to height as high, average, and shallow. Illustrations and cadaver dissection are utilized to demonstrate that surgeons can gain substantial donor tissue specimens without encountering the neurovascular bundle. Actions to be followed in the unlikely event that the neurovasculature is encountered are reviewed.

Growth hormone-releasing factor expression is discordantly regulated in the hypothalamus and testis of streptozotocin-diabetic rats.

Growth hormone-releasing factor (GRF) mRNA expression in male rats occurs predominantly in the hypothalamus (mainly in the arcuate nucleus), and among extraneural sites primarily in the testis. Hypothalamic GRF is the physiological tropic stimulus to growth hormone secretion. However, the role of GRF in the testis is unknown. We have shown previously that hypothalamic GRF mRNA expression is significantly reduced in streptozotocin (STZ)-diabetic rats. This reduction is confined to the arcuate nucleus and probably accounts for the suppression of growth hormone pulsatility. The present studies were performed to evaluate GRF expression in the testis of streptozotocin (STZ)-diabetic rats. Diabetes was induced by injection of STZ (100 mg/kg i.p.). Seventeen to twenty days later diabetic rats were hyperglycemic compared with vehicle-injected controls and demonstrated growth failure. Insulin treatment reduced the glycemia and increased body weight towards normal. Total RNA was extracted from the hypothalamus and testis, and GRF mRNA levels estimated by solution hybridization/nuclease protection assay. Levels of hypothalamic somatostatin mRNA were measured to serve as control values. GRF mRNA was significantly (P < 0.001) decreased in the hypothalamus of STZ-diabetic rats (0.2 +/- 0.07 mean relative densitometric units, n = 8) compared with controls (1.0 +/- 0.19, n = 8) with no change in somatostatin mRNA expression. In contrast, testicular GRF mRNA was increased 70% (P < 0.05) in STZ-diabetic rats. Insulin treatment resulted in normalization of hypothalamic GRF mRNA levels (1.1 +/- 0.17, n = 5) with no effect on testicular GRF mRNA expression. In conclusion GRF gene expression is discordantly regulated in tissues of male STZ-diabetic rats. While reduced GRF expression may account for the low growth hormone state in this model, increased testicular GRF mRNA (with the previously reported reduction of insulin-like growth factor-I mRNA) resembles the response seen in growth hormone-sensitive tissue (especially the hypothalamus) to this growth hormone-deficient state.

Dexamethasone regulates somatostatin receptor subtype messenger ribonucleic acid expression in rat pituitary GH4C1 cells.

Ligand binding studies have shown that glucocorticoids down-regulate somatostatin receptor (sst) concentration in several endocrine target cells and cell lines including GH4C1 cells. However, it has not been determined whether this decrease in sst number occurred via transcriptional and/or posttranscriptional events. In the present study, we have investigated the effect of dexamethasone (Dex) treatment (1 microM) of GH4C1 cells for up to 48 h on the steady state level of messenger RNA (mRNA) for sst1, sst2, and sst3, the predominant isoforms expressed in this cell line, by solution hybridization-nuclease protection analysis. Exposure of GH4C1 cells to Dex for 2 h increased sst1 mRNA levels 2.5-fold and sst2 1.5-fold compared with controls (Con). Prolonged exposure, however, resulted in a decrease in mRNA levels of sst1 to 50% and sst2 to 30% of Con by 24-48 h. In contrast, sst3 mRNA levels were unchanged at 2 h, decreased to 30% of Con by 6 h, and remained decreased for up to 24 h. Longer exposure resulted in a dramatic increase in expression, reaching 350% of Con by 48 h. The Dex effect on expression of all subtypes was dose dependent, maximal at 10 nM. Steroid hormone regulation of sst mRNA expression in GH4C1 cells proved to be complex. Exposure to Dex for 24 h, as expected, decreased expression of all subtypes. Progesterone, however, increased sst1 mRNA levels, decreased sst3 levels, but was without effect on sst2; treatment with estrogen and testosterone increased expression of all three subtypes. Nuclear run-on assays indicated that the Dex-induced changes in sst1 and sst2 mRNA levels were associated with congruent changes in the transcription rate of sst genes. Thus, glucocorticoids regulate sst expression in GH4C1 cells, at least in part, by controlling the rate of transcription of sst genes.

Characterization of the proximal promoter region of the rat somatostatin receptor gene, SSTR4.

In the present study, the putative promoter region of rSSTR4 gene has been cloned and characterized. Primer extension and RNAase protection analysis reveals the existence of multiple transcriptional initiation sites, the five major ones mapping between -126 and -18 relative to the ATG initiation codon. Sequence analysis reveals that the region lacks TATA and CCAAT promoter elements, possesses a high GC content and contains a number of potential SP1 binding sites. In addition, potential AP-2, GCF, and PuF binding sites and an octimer motif were also identified. Thus, the promoter of rSSTR4 shows similar features to promoters of highly regulated growth factor receptors and oncogenes. The potential role these transcriptional binding sites play in regulating rSSTR4 expression is currently being investigated.

Regulation of somatostatin receptor mRNA expression.

The five somatostatin receptor mRNAs are expressed with distinct though overlapping patterns of distribution in the CNS and peripheral tissues. All receptor types are expressed in the anterior pituitary and hypothalamus and could therefore be modulated in states of growth hormone (GH) dysregulation. Metabolic perturbations such as food deprivation and diabetes mellitus lead to suppression of GH levels in the rat, in part due to increased somatostatin tone. In rats deprived of food, pituitary sstr1, 2 and 3 mRNAs were reduced by 80% compared to fed controls; sstr4 and sstr5 mRNAs were unchanged. Hypothalamic sstr mRNA expression was unaltered. In diabetic rats pituitary sstr1, 2 and 3 mRNAs were reduced by 50-80% with sstr1 mRNA restored in part by insulin therapy. Pituitary sstr4 mRNA and hypothalamic expression of these four types was unaffected. sstr5 mRNA is reduced by 70% in the pituitary and by 30% in the hypothalamus with restoration of both by insulin treatment. Altered pituitary sstr expression in food deprivation and diabetes could result from chronic exposure to increased plasma somatostatin. In rat GH3 pituitary tumour cells exposed to 1 microM somatostatin for up to 48 h, sstr1, 3, 4 and 5 mRNA increased dramatically while sstr2 mRNA exhibited a biphasic response. We observed a net increase in receptor binding associated with increased sstr mRNA. Somatostatin receptor expression is regulated in a tissue- and type-specific manner, adding further complexity to the action of the multifaceted peptide somatostatin.

Pituitary and hypothalamic somatostatin receptor subtype messenger ribonucleic acid expression in the food-deprived and diabetic rat.

Prolonged food deprivation (FD) and streptozocin-induced diabetes (STZ diabetes) in the rat result in abolition of GH secretory episodes. We have previously shown that hypothalamic prepro-GRF messenger RNA (mRNA) expression is markedly reduced in the hypothalamus of FD and STZ diabetic rats, with no change in prepro-somatostatin (SRIF) mRNA and suggested that reduced GRF and increased SRIF tone explained the loss of GH secretion in FD and STZ diabetes. Altered SRIF peptide expression has been implicated in many physiological and pathological states; however, information on the regulation of SRIF receptor (SSTR) expression is lacking. Therefore, we examined the expression of mRNA for the five recently cloned SSTR subtypes in the pituitary and hypothalamus of FD and STZ diabetic rats. In addition, we measured SRIF binding to pituitary membranes of FD rats. SSTR1, SSTR2, and SSTR3 mRNA expression was reduced 80% in the pituitary of FD rats vs. fed controls, whereas pituitary levels of SSTR4 and SSTR5 mRNA were unaffected. The pituitary plasma membrane SSTR concentration was reduced over 50% in FD vs. fed animals. However, hypothalamic levels of the five isoforms were unchanged. In STZ diabetes, pituitary SSTR1, SSTR2, and SSTR3 mRNA expression was reduced 50-80%, with levels of SSTR1 partially restored by insulin, whereas SSTR4 mRNA was unchanged. In contrast to the effect of FD, SSTR5 mRNA levels were reduced 70% in the pituitary and 30% in the hypothalamus of STZ diabetic rats, with complete restoration by insulin. Thus, SSTR subtype mRNA expression is differentially regulated in two models of GH deficiency in the rat, FD and STZ diabetes. As chronic exposure to SRIF results in desensitization of transfected SSTR2 and SSTR3, and SSTR binding is decreased in FD and STZ diabetic rats, the possibility exists that the pituitary changes result from continued exposure to SRIF. In the hypothalamus, however, regulation appears more complex. These data support a role of increased SRIF with decreased GRF in mediating the loss of GH secretion in FD and diabetes.

Somatostatin regulates somatostatin receptor subtype mRNA expression in GH3 cells.

Homologous up-regulation of somatostatin receptors (SSTR) was investigated in the GH3 clonal pituitary cell line. We report that chronic exposure to SRIF which has high affinity for all SSTR subtypes leads to a net increase in receptor binding and SSTR subtype mRNA. Treatment of cells with 1 microM SRIF increased specific [125I-Tyr11]SRIF binding to 280% of control values by 24 hr and to 350% by 48hr. Associated with the increase in SSTR binding was a net increase in SSTR subtype mRNA expression. Levels of SSTR1 increased to over 400% of control values by 6 hr and remained elevated for up to 48 hr. SSTR3, SSTR4, and SSTR5 mRNA was also dramatically increased at 24 and 48 hr. SSTR2 mRNA, in contrast, showed a biphasic response, initially increasing to 150% of control at 2 hr then decreasing to 50% at 6 hr with normalization by 48 hr. Our data suggests that multiple mechanisms contribute to the highly regulated expression of SSTR subtypes. The identification of specific molecular and cellular mechanisms mediating homologous SSTR up-regulation in GH3 cells and the involvement this process has in mediating the diverse biological effects of somatostatin are topics of current research.

Connective tissue graft technique assuring wide root coverage.

Gingival recession related to periodontal disease or developmental problems can result in root sensitivity, root caries, and esthetically unacceptable root exposures. Consequently, root restorations are performed that often complicate, rather than resolve, the problems created by exposed roots. This article presents a predictable procedure for root coverage on areas of wide denudation in the maxilla and the mandible.

Tissue distribution of somatostatin receptor subtype messenger ribonucleic acid in the rat.

The tissue distribution of mRNA encoding five somatostatin receptor subtypes, SSTR1, SSTR2, SSTR3, SSTR4, and SSTR5, was determined in adult rat tissues by solution hybridization/nuclease protection analysis using sequence-specific cRNA probes. In the central nervous system, SSTR1 and SSTR2 mRNA were expressed widely, with highest levels in hippocampus, hypothalamus, cortex, and amygdala and expression of both isoforms in cerebellum and spinal cord. Expression of SSTR3 was also widespread, occurring in all brain regions examined, with the highest level of expression in the cerebellum. SSTR4 mRNA was detected in most brain regions, with highest levels occurring in the hippocampus, cortex, and olfactory bulb. No detectable levels were found in cerebellum. SSTR5 showed a unique pattern of expression in the central nervous system, being found primarily in the hypothalamus and preoptic area. In peripheral tissues, high levels of SSTR1 and SSTR2 mRNA were found in pituitary and spleen. SSTR1 mRNA was also found in the heart and intestine, SSTR2 was detected in pancreas, and both isoforms were expressed in stomach. Expression of SSTR3 was noted in heart, liver, stomach, intestine, kidney, spleen, and pituitary. The patterns of expression were similar for SSTR4 and SSTR3 mRNA; however, SSTR4 was not expressed in liver. SSTR5 was expressed predominantly in the pituitary, but detectible levels were observed in spleen and intestine. Thus, the SSTR subtype mRNA showed both a tissue-specific and overlapping pattern of expression. Taken together with SSTR-specific signal transduction systems, this probably explains the diverse physiological actions of somatostatin.

Regulation of hypothalamic preprogrowth hormone-releasing factor messenger ribonucleic acid expression in food-deprived rats: a role for histaminergic neurotransmission.

To determine the component(s) of dietary protein that regulates GH-releasing factor (GRF) synthesis, we measured hypothalamic prepro-GRF mRNA by solution hybridization/nuclease protection analysis in food-deprived rats refed protein-free diets (PF) supplemented with individual amino acids. Adult male Sprague-Dawley rats were allowed free access to food (Fed), food deprived for 72 h (FD), or FD then refed for 72 h with a normal (NF) diet, a protein-free (PF) diet, or PF diets containing tyrosine, tryptophan (Trp), glutamic acid, or histidine (His). Food-deprived rats displayed the expected 80% reduction in hypothalamic prepro-GRF mRNA. Upon refeeding, levels were normalized in rats refed a normal diet, but not in those refed a PF diet alone or with tyrosine, Trp, or glutamic acid. In contrast, prepro-GRF mRNA was restored to 70% of Fed values by a PF diet with His. Supplementing a PF diet with His was sufficient to maintain hypothalamic prepro-GRF mRNA expression, as 3 days of feeding replete rats with PF diet or PF diet with added Trp resulted in a 50% reduction in prepro-GRF mRNA, whereas levels were reduced 25% by feeding animals a PF diet with His. Groups of rats allowed free access to food were treated for 72 h with two daily injections of 100 mg/kg alpha-fluoremethylhistidine, a specific irreversible inhibitor of histidine decarboxylase, to determine if the effect of His on prepro-GRF mRNA depended on neural conversion to histamine. alpha-Fluoremethylhistidine-treated rats showed a 40% reduction in hypothalamic prepro-GRF mRNA, with no concomitant change in preproneuropeptide-Y or preprosomatostatin. These data indicate that decreased hypothalamic prepro-GRF mRNA in FD rats is due in part to the lack of dietary and provide clear evidence for a role of the histaminergic neural system in the regulation of hypothalamic GRF expression.

Molecular cloning and sequencing of a human somatostatin receptor, hSSTR4.

We recently reported the cloning of a somatostatin receptor (SSTR) subtype from a rat genomic library designated rSSTR4. In the present study, we report the cloning of the human SSTR4 gene. A human genomic library was screened with a 1.2 kb fragment of rSSTR4 containing the full open reading frame and a genomic clone, hSSTR4, was isolated. The deduced amino acid sequence of this clone encoded a protein of 388 amino acids and is a member of the G-protein coupled receptor superfamily. Comparison of rat and human SSTR4 sequences demonstrated 89% identity. In addition, the sequence of hSSTR4 shows 61%, 46%, and 47% sequence identity with previously identified isoforms hSSTR1, hSSTR2, and hSSTR3, respectively.

Pituitary and hypothalamic insulin-like growth factor-I (IGF-I) and IGF-I receptor expression in food-deprived rats.

The present study was designed to evaluate a possible role for the insulin-like growth factor-I (IGF-I) system in mediating the suppression of growth hormone (GH) secretion observed in food-deprived rats by measuring IGF-I mRNA, receptor concentration and receptor mRNA in neuroendocrine tissues (hypothalamus and pituitary). Rats were deprived of food (food-deprived) for 72 h or had free access to food (fed). Tissues were processed for measurement of steady-state levels of: (a) IGF-I and IGF-I receptor mRNA (by solution hybridization/RNase protection assay); (b) IGF-I in serum and tissue extracts (by RIA) and (c) IGF-I displaceable [125I]IGF-I binding to plasma membrane preparations. Food deprivation resulted in decreased serum and liver levels of IGF-I. Kidney IGF-I mRNA levels were reduced 80% in food-deprived rats with a concomitant increase in IGF-I receptor concentration and mRNA levels. Refeeding of food-deprived rats fully normalized these perturbations. Pituitary IGF-I content was reduced 50% in food-deprived rats while IGF-I mRNA levels were unaffected. A modest increase was seen in pituitary IGF-I receptor concentration; however, IGF-I receptor mRNA levels were not changed. Hypothalamic IGF-I mRNA content was reduced in 72 h food-deprived rats while IGF-I receptor binding capacity and mRNA were unaffected. In conclusion, IGF-I mRNA levels are decreased in liver, kidney and hypothalamus together with a reduction in plasma IGF-I in food-deprived rats but is unaffected in anterior pituitary. IGF-I receptor gene expression and binding capacity are coordinately regulated in kidney and hypothalamus, but not in the pituitary.(ABSTRACT TRUNCATED AT 250 WORDS)

Ligand Binding and Functional Properties of the Rat Somatostatin Receptor SSTR4 Stably Expressed in Chinese Hamster Ovary Cells.

Somatostatin (SS14) is an important regulator of endocrine and brain function exerting its action after binding to high-affinity membrane receptor subtypes. Its diverse physiological activities include inhibition of hormone secretion from pituitary, pancreas, and gut. In the CNS, SS14 acting as a neurotransmitter/neuromodulator exerts inhibitory effects on neural function. Recently, three SS14 receptor genes, SSTR1, SSTR2, and SSTR3, have been cloned and characterized. We have cloned and characterized a novel fourth member of this gene family from a rat genomic library, SSTR4, which is expressed predominantly in neural tissue. When stably expressed in CHO-K1 cells, SSTR4 binds SS14 and SS28 with high affinity; however, the SS14 analogs SMS 201-995 and MK 678 failed to displace specific binding. High-affinity agonist binding was diminished by prior exposure to both GTPgammaS and pertussis toxin (PTX) but was not effected following agonist pretreatment, indicating that SSTR4 is coupled to a PTX-sensitive G-protein but does not desensitize. SSTR4 expressed in CHO cells is coupled by a PTX-sensitive G-protein to inhibition of adenylyl cyclase since treatment of transfected cells with SS14 resulted in the inhibition of forskolin-stimulated cAMP accumulation, an effect that was abolished by PTX treatment. The cloning of four SS14 receptor subtypes provide molecular probes for structure-function studies and for identifying those particular subtypes responsible for mediating the diverse physiological action of SS14.