The effects of ethanol and chlorpromazine on the passive membrane permeability to Na

1.

1. Chlorpromazine and ethanol each reduced the passive influx of Na⁺ into resting sartorius muscle (frog) incubated in a medium containing 1 mM Ca²⁺, ouabain (to preclude active fluxes) and isotonic choline chloride (to preclude membrane depolarization).     

Structure and variation of three canine genes involved in serotonin binding and transport: the serotonin receptor 1A gene (htr1A), serotonin receptor 2A gene (htr2A), and serotonin transporter gene (slc6A4)

Aggressive behavior is the most frequently encountered behavioral problem in dogs. Abnormalities in brain serotonin metabolism have been described in aggressive dogs. We studied canine serotonergic genes to investigate genetic factors underlying canine aggression. Here, we describe the characterization of three genes of the canine serotonergic system: the serotonin receptor 1A and 2A gene (htr1A and htr2A) and the serotonin transporter gene (slc6A4). We isolated canine bacterial artificial chromosome clones containing these genes and designed oligonucleotides for genomic sequencing of coding regions and intron-exon boundaries. Golden retrievers were analyzed for DNA sequence variations. We found two nonsynonymous single nucleotide polymorphisms (SNPs) in the coding sequence of htr1A; one SNP close to a splice site in htr2A; and two SNPs in slc6A4, one in the coding sequence and one close to a splice site. In addition, we identified a polymorphic microsatellite marker for each gene. Htr1A is a strong candidate for involvement in the domestication of the dog. We genotyped the htr1A SNPs in 41 dogs of seven breeds with diverse behavioral characteristics. At least three SNP haplotypes were found. Our results do not support involvement of the gene in domestication.     

Estimation of levels of serotonin and 5-hydroxyindoles in whole blood by an autoanalytical procedure: observations on the blood-brain barrier

Abstract— We describe a method for the fluorometric determination of 5-hydroxyindoles in the physiological range of 0.010–1.30 μg/ml of whole blood by means of an autoanalytical procedure. Serotonin is dialysed free from haemolysed blood constituents and a complex between 5-HT and o-phthaldialdehyde is formed in the dialysand to provide a considerable increase over the native fluorescence of 5-HT in strong acid. The method has been evaluated and considered to be accurate for the continuous monitoring of levels of 5-HT in whole blood and for the determination of cerebral arteriovenous differences. The range of values for human patients with cerebrovascular disease was 0.09–0.34 μg/ml of whole blood. In experimental studies on the baboon the range was 0.538–1.28 μg/ml. A mean positive cerebral arteriovenous difference for 5-HT (and possibly other 5-hydroxyindoles) of 0.037 μg/ml was measured in 10 baboons. This finding suggests the possibility of physiological movement of 5-HT and 5-hydroxyindoles into brain across the blood-brain barrier.     

The effect of plant size on vegetative reproduction in a pseudo-annual

The relationship between plant size and vegetative reproduction in clonal plants appears complex because vegetative expansion, growth, and reproduction are not clearly separable in such plants. In pseudo-annuals, which are clonal plants surviving the winter only as seeds and hibernacles produced by the rhizome apices, vegetative growth and reproduction are clearly separate processes so that the relationship between vegetative reproduction and plant size can be studied. We used the pseudo-annual Helianthus x laetiflorus Pers. to study the relationship between plant size and total rhizome biomass, rhizome (hibernacle) biomass, and number of hibernacles. We manipulated resource acquisition of the plants by reducing leaf area (leaf-clipping) and by fertilization, thus affecting plant size. Furthermore, we studied the success of thin and thick hibernacles in terms of future growth and reproduction in a separate experiment. The results showed that vegetative reproduction was positively related to plant size. The ratio between the number of hibernacles and mean hibernacle weight was affected by plant size in such a way that in small plants both number of hibernacles and mean hibernacle weight were reduced to the same extent as compared to those in large plants.However, the size distributions of plants of the next generation growing from thin and thick hibernacles did not differ. It remains unclear therefore why this pseudo-annual species produces thick hibernacles at all.