Role of 5-HT2C receptors in zebrafish alarm reactions and post-exposure behavior

Serotonin (5-HT) receptors have been implicated in responses to aversive stimuli in mammals and fish, but its precise role is still unknown. Moreover, since at least seven families of 5-HT receptors exist in vertebrates, the role of specific receptors is still debated. Aversive stimuli can be classified as indicators of proximal, distal, or potential threat, initiating responses that are appropriate for each of these threat levels. Responses to potential threat usually involve cautious exploration and increased alertness, while responses to distal and proximal threat involve a fight-flight-freeze reaction. We exposed adult zebrafish to a conspecific alarm substance (CAS) and observed behavior during (distal threat) and after (proximal threat) exposure, and treated with the 5-HT2C receptor agonists MK-212 or WAY-161503 or with the antagonist RS-102221. The agonists blocked CAS-elicited defensive behavior (distal threat), but not post-exposure increases in defensive behavior (potential threat), suggesting a phasic inhibition of responses to distal threat. MK-212 did not block changes in behavior elicited by acute restraint stress, a model of proximal threat, suggesting that the phasic role of the 5-HT2C receptor is specific to distal threat. We also found that RS-10221, a 5-HT2C receptor antagonist, did not change behavior during exposure, but it produced a small effect on behavior after exposure to CAS, suggesting a tonic facilitation of responses to potential threat.

Analisis genotip normal dan abnormal pada klon kelapa sawit (Elaeis guineensis Jacq.) dengan Amplified Fragment Length Polymorphism (AFLP) Analysis normal and abnormal genotypes of oil palm clones (Elaeis guineensis Jacq.) by Amplified Fragment Length Polymorphism (AFLP)

SummaryTissue culture-derived plants of oil palmmay develop abnormal flowers in whichprimordial stamens are converted into carpel-liketissue or mantled fruits, and sterile male flowers.This abnormality can be heritable, individualpalm may show variation in mantling andreversion to the normal phenotype over time hasbeen observed. The aim of these experiments wasto analyze the differences between normal andabnormal genotypes by DNA-AFLP. DNA wasisolated from young fruits of three clones,MK152, MK209, and MK 212 each of themconsisted of normal fruits, abnormal fruits andsterile male flowers. The research consisted of (i)selection of AFLP primer which can producepolymorphic bands, (ii) genetic similaritiesanalysis, UPGMA, principal component analysisand specific DNA bands between normal orabnormal genotypes. For primers selection, 20AFLP primers with DNA from MK 152 normaland abnormal genotypes were used. The selectedprimers were then used to amplify DNA of ninegenotypes. The results show that 10 primer com-binations EcoRI/MseI produced polymorphicbands. Each primer from 10 primer producedonly one or two DNA bands indicates that thedifferences between normal and abnormalgenotypes in the same clone. However, nopolymorphism was consistently found betweennormal and abnormal clones in all the sets.Genetic similarity analysis shows that betweengenotype had high genetic similarities, around92-99%. The results of UPGMA found thedifferent clustering between normal fruit,abnormal male and abnormal fruits. The resultsshow same as clustering based on first, secondand third component. This suggest that, whilstAFLP method is an effective way of detectingvariation in tissue culture-derived plants,different approaches are required to identify thecasual basis of the mantled fruit abnormality.RingkasanTanaman kelapa sawit yang dihasilkan darikultur jaringan, umumnya dalam perkembangan-nya akan memiliki organ reproduktif yangabnormal. Abnormalitas berupa primordialstamen berkembang menjadi bentuk jaringanseperti karpel, buah mantel, atau bunga jantanmandul. Penelitian ini bertujuan untukmendapatkan pembeda DNA-AFLP antaragenotip normal dan abnormal pada klon-klonkelapa sawit. DNA diisolasi dari buah muda klonMK 152, MK 209, dan MK 212 yang masing-masing terdiri atas genotip normal, berbuahabnormal, dan berbunga jantan steril. Percobaanmencakup (i) seleksi primer AFLP yang mampumenghasilkan pita yang polimorfis, (ii) analisiskemiripan genetik, UPGMA, komponen utamadan pita pembeda antar genotip normal danabnormal. Seleksi primer dilakukan terhadap 20primer AFLP menggunakan DNA dari genotipMK 152 yang normal dan abnormal. Selanjutnyaprimer terpilih digunakan untuk mengamplifikasiDNA dari kesembilan genotip yang diuji. Hasilyang diperoleh menunjukkan bahwa 10 kombi-nasi primer EcoRI/MseI mampu menghasilkanpita yang polimorfis. Dari 10 primer yang diuji,masing-masing hanya menghasilkan satu ataudua pita DNA yang mampu membedakan genotipnormal dan abnormal dalam klon yang sama.Namun, tidak ada pita DNA spesifik yangmampu membedakan genotip normal denganabnormal untuk seluruh klon yang diuji. Analisiskemiripan genetik menunjukkan bahwa antargenotip memiliki kemiripan genetik yang sangattinggi, yaitu 92-99%. Dari hasil UPGMAdiperoleh pengelompokan yang terpisah antargenotip normal, abnormal jantan dan buahabnormal. Hasil tersebut didukung olehpengelompokan berdasarkan komponen utamasatu, dua dan tiga. Dapat disimpulkan bahwa,teknik AFLP tidak efektif untuk mendeteksipembeda antar genotip tanaman yang diperolehdari kultur jaringan, pendekatan lainnyadiperlukan untuk mengidentifikasi abnormalitas.

Analisis genotip normal dan abnormal pada klon kelapa sawit (Elaeis guineensis Jacq.) dengan Amplified Fragment Length Polymorphism (AFLP) Analysis normal and abnormal genotypes of oil palm clones (Elaeis guineensis Jacq.) by Amplified Fragment Length Polymorphism (AFLP)

SummaryTissue culture-derived plants of oil palmmay develop abnormal flowers in whichprimordial stamens are converted into carpel-liketissue or mantled fruits, and sterile male flowers.This abnormality can be heritable, individualpalm may show variation in mantling andreversion to the normal phenotype over time hasbeen observed. The aim of these experiments wasto analyze the differences between normal andabnormal genotypes by DNA-AFLP. DNA wasisolated from young fruits of three clones,MK152, MK209, and MK 212 each of themconsisted of normal fruits, abnormal fruits andsterile male flowers. The research consisted of (i)selection of AFLP primer which can producepolymorphic bands, (ii) genetic similaritiesanalysis, UPGMA, principal component analysisand specific DNA bands between normal orabnormal genotypes. For primers selection, 20AFLP primers with DNA from MK 152 normaland abnormal genotypes were used. The selectedprimers were then used to amplify DNA of ninegenotypes. The results show that 10 primer com-binations EcoRI/MseI produced polymorphicbands. Each primer from 10 primer producedonly one or two DNA bands indicates that thedifferences between normal and abnormalgenotypes in the same clone. However, nopolymorphism was consistently found betweennormal and abnormal clones in all the sets.Genetic similarity analysis shows that betweengenotype had high genetic similarities, around92-99%. The results of UPGMA found thedifferent clustering between normal fruit,abnormal male and abnormal fruits. The resultsshow same as clustering based on first, secondand third component. This suggest that, whilstAFLP method is an effective way of detectingvariation in tissue culture-derived plants,different approaches are required to identify thecasual basis of the mantled fruit abnormality.RingkasanTanaman kelapa sawit yang dihasilkan darikultur jaringan, umumnya dalam perkembangan-nya akan memiliki organ reproduktif yangabnormal. Abnormalitas berupa primordialstamen berkembang menjadi bentuk jaringanseperti karpel, buah mantel, atau bunga jantanmandul. Penelitian ini bertujuan untukmendapatkan pembeda DNA-AFLP antaragenotip normal dan abnormal pada klon-klonkelapa sawit. DNA diisolasi dari buah muda klonMK 152, MK 209, dan MK 212 yang masing-masing terdiri atas genotip normal, berbuahabnormal, dan berbunga jantan steril. Percobaanmencakup (i) seleksi primer AFLP yang mampumenghasilkan pita yang polimorfis, (ii) analisiskemiripan genetik, UPGMA, komponen utamadan pita pembeda antar genotip normal danabnormal. Seleksi primer dilakukan terhadap 20primer AFLP menggunakan DNA dari genotipMK 152 yang normal dan abnormal. Selanjutnyaprimer terpilih digunakan untuk mengamplifikasiDNA dari kesembilan genotip yang diuji. Hasilyang diperoleh menunjukkan bahwa 10 kombi-nasi primer EcoRI/MseI mampu menghasilkanpita yang polimorfis. Dari 10 primer yang diuji,masing-masing hanya menghasilkan satu ataudua pita DNA yang mampu membedakan genotipnormal dan abnormal dalam klon yang sama.Namun, tidak ada pita DNA spesifik yangmampu membedakan genotip normal denganabnormal untuk seluruh klon yang diuji. Analisiskemiripan genetik menunjukkan bahwa antargenotip memiliki kemiripan genetik yang sangattinggi, yaitu 92-99%. Dari hasil UPGMAdiperoleh pengelompokan yang terpisah antargenotip normal, abnormal jantan dan buahabnormal. Hasil tersebut didukung olehpengelompokan berdasarkan komponen utamasatu, dua dan tiga. Dapat disimpulkan bahwa,teknik AFLP tidak efektif untuk mendeteksipembeda antar genotip tanaman yang diperolehdari kultur jaringan, pendekatan lainnyadiperlukan untuk mengidentifikasi abnormalitas.

Genotype-Dependent Difference in 5-HT2CReceptor-Induced Hypolocomotion: Comparison with 5-HT2AReceptor Functional Activity

In the present study behavioral effects of the 5-HT2Cserotonin receptor were investigated in different mouse strains. The 5-HT2Creceptor agonist MK-212 applied intraperitoneally induced significant dose-dependent reduction of distance traveled in the open field test in CBA/Lac mice. This effect was receptor-specific because it was inhibited by the 5-HT2Creceptor antagonist RS102221. To study the role of genotype in 5-HT2Creceptor-induced hypolocomotion, locomotor activity of seven inbred mouse strains was measured after MK-212 acute treatment. We found that the 5-HT2Creceptor stimulation by MK-212 decreased distance traveled in the open field test in CBA/Lac, C57Bl/6, C3H/He, and ICR mice, whereas it failed to affect locomotor activity in DBA/2J, Asn, and Balb/c mice. We also compared the interstrain differences in functional response to 5-HT2Cand 5-HT2Areceptors activation measured by the quantification of receptor-mediated head-twitches. These experiments revealed significant positive correlation between 5-HT2C and 5-HT2A receptors functional responses for all investigated mouse strains. Moreover, we found that 5-HT2Areceptor activation with DOI did not change locomotor activity in CBA/Lac mice. Taken together, our data indicate the implication of 5-HT2Creceptors in regulation of locomotor activity and suggest the shared mechanism for functional responses mediated by 5-HT2Cand 5-HT2Areceptors.