Notes: Mass-fragmentographic methods are described that enable the simultaneous measurement of total, free, and conjugated catecholamines in brain tissues. These methods were used to assess the distribution, kinetics, and pharmacological characteristics of total, free, and conjugated catecholamines in the hypothalamus, caudate nucleus, hippocampus, and septum. Conjugated norepi-nephrine (NE) represents ˜20% of total NE in the hypothalamus, septum, and hippocampus, whereas the percentage is ˜ 50% in the caudate nucleus. The percentages of conjugated dopamine (DA) in these brain areas are consistently less than those of NE (˜13%). Although in the hypothalamus the steady-state concentrations of total, free, and conjugated NE are over four times higher than those of the corresponding total, free, and conjugated DA, the turnover rates of this DA are comparable with those of the corresponding NE. Further, the ratios of conjugated NE or DA turnover rates to those of the total amines are higher than the corresponding ratios of their steady-state concentrations. Treatments with pargyline (75 mg/kg, i.p.; rats killed 30 and 60 min later) failed to change the contents of conjugated catecholamines in the hypothalamus and the caudate nucleus significantly. Pharmacological manipulation with a number of proto-typic drugs revealed that although the assay of conjugated catecholamines might shed additional light on the effects of drugs on central catecholamines, the assessment of total or free amines are on the whole equally informative. In conclusion, a detailed assessment of brain conjugated catecholamines is reported. The information provided, fills a gap in our knowledge that has up to now not been adequately addressed.

Notes: Abstract— Vanillylmandelic acid (VMA) and 3-methoxy-4- hydroxyphenylglycol (MHPG) were measured in rat brain by a mass fragmentographic procedure. The concentration of VMA and MHPG in whole brain is 11 and 533 pmol/g, respectively. Both compounds were found in all areas of brain studied with VMA, as a percentage of both metabolites, ranging between about 1 and 8%. From the decline of the compounds after pargyline. 75 mg/kg i.p., we calculated that the rate of formation of VMA is 15 and for MHPG 202 pmol/g per h. The fractional rate of elimination of VMA and MHPG is 1.4 and 0.38 h−1, respectively. The rapid rate of loss of VMA suggests that it is transported from brain. However, we were unable to block the elimination of VMA from brain by treatment with probenecid. In contrast, the elimination of MHPG could be blocked by treatment with probenecid. Our study adds support to the notion that MHPG is a major whereas VMA is a minor product of norepinephrine metabolism in brain.

Notes: —A mass fragmentographic procedure is described for the simultaneous quantification of a number of deaminated metabolites derived from tyramine, octopamine, dopamine, and norepinephrine. With this method, several of the metabolites were measured in normal rat brain. The results support the central nervous system origin of tyramine, octopamine and their metabolites. The concentration of the dopamine metabolite, homovanillic acid, in the rat brain was found to be about 15% higher than that of dihydroxyphenylacetic acid. As for the metabolites of norepinephrine, vanilmandelic acid concentration was found to be about 5% that of 3-methoxy-4-hydroxyphenylglycol. The possible role of vanilmandelic acid in the CNS metabolism of norephrine is discussed.

Notes: —A mass fragmentographic method for the assay of phenylethylamine (PEA) and a number of related amines in several biological materials is described. The gas chromatographic column employed for this analysis is a 12ft 1/8 in. o.d. steel column packed with 0.5% OV22+ 2% SE54 + 1% OV210 coated on 80/100 mesh chromosorb W (HP). The mass spectral characteristics of these amines are illustrated, compared, and discussed.Of the various monoamines which could be measured, only PEA, m- and p-tyramine were detected in measurable quantities. Phenylethanolamine and p-octopamine were found in trace amounts in urine, plasma, cerebrosponal fluid, and rat brain. No diurnal variation in the urinary excretion of PEA, m- and p-tyramine was observed. Plasma concentration of PEA or p-tyramine did not significantly change 1 h after eating a breakfast. Furthermore, consuming 200 g of Cadbury milk chocolate containing about 1 mg of PEA, 0.1 mg of phenylethanolamine and 10 mg of p-tyramine did not significantly alter urine excretions of these three amines.In the brain, as has been reported by others, we found that PEA and p-tyramine are not evenly distributed and that the highest concentrations are found in the hypothalamus and caudate.From the results obtained we concluded that PEA, m- and p-tyramine are probably produced from endogenous sources and that the direct contribution of diet to their urine excretion is small.

Notes: Investigations into the biology of the roach and the pathogenic tapeworm Ligula intestinalis (L.) populations at Slapton Ley, Devon were carried out between October 1982 and December 1984. Data collected from the lake since 1977 have also been re-analysed to determine how the dramatic improvement in the individual growth rate of the roach over this period may have affected the growth, maturation and life-cycle of Ligula. Only the very young roach at this site become infected, so it was possible to follow cohorts of plerocercoids of similar age through each roach year class. Results for the 1978 and 1983 year classes are presented in detail. The roach grew extremely rapidly from May to August in each year, resulting in a pronounced cyclical pattern of changes in the condition of the roach, with the lowest condition occurring in late winter and spring. The yearly increase in the roach growth rate was accompanied by an increase in plerocercoid growth rate in the 0 + roach, but not in the 1 + roach. The growth rate of the plerocercoids was very high compared to that at other sites. It is usual for the parasite index (PI) of Ligula-infected fish to be high and to increase throughout their first few years of life. At Slapton, however, a lack of multiple infections has prevented high PIs from occurring, and in recent years the growth rate of the roach has been so high that the plerocercoids were unable to maintain a high weight relative to the fish, and the highest PIs occurred in the 0 + roach throughout late winter and spring. In recent year classes, therefore, the maximum PIs and highest pathogenicities coincided with the period of lowest condition in the 0+ roach. Observations of both caged and natural populations of 0+ roach over winter showed that a significant loss of roach containing the larger plerocercoids occurred from the population. In vitro cultivation of Ligula plerocercoids showed that they were capable of maturation at weights of 0.5 g, and only 6 months after having infected the roach. The increase of the growth rate of the plerocercoids in the 0+ roach has therefore resulted in a greater proportion of these plerocercoids being capable of infecting the definitive host. As a result of the increase in individual growth rate of the roach at Slapton, the potential for Ligula transmission, as measured in terms of both their pathogenicity and maturity, has shifted from the 1 + to the 0+ roach.

Notes: Investigations into the biology of the roach population at Slapton Ley, Devon, U.K. were carried out between October 1982 and December 1984 and data collected from the lake since 1977 have been re-analysed to assist interpretation. The roach population has been characterized in recent years by extreme year class variation and a tendency for year classes to alternate in strength. The survival of the roach was very poor, and the spawning population therefore consisted largely of 2-and some 3-year-old fish. Consequently, the size of the spawning stock was small and dependent on the strengths of the year classes that it contained. Recruitment to many year classes was probably limited by the size of the spawning stock. The occurrence of a poor year class in the population would therefore set up an autonomous cycle of poor recruitment to alternate year classes in a manner similar to many tropical marine fisheries. Observation of other British roach populations showed that a short life-span may be associated with conditions that promote very rapid growth rates. The growth rate of individual roach at Slapton was found to be one of the fastest in Britain, and this was apparently due to the very high productivity of Slapton Ley together with the persistence of the roach population at very low densities.

Notes: The effective management of salmonid fisheries requires that the factors influencing variation in the abundance of stream populations are understood. The use of habitat models to explain the spatial component of population variance offers potential for management, but has not previously been set in the context of long term variation in population abundance because of the lack of suitable data sets. This paper examines contributions of spatial and temporal factors lo fish density variance using a 10-year data set from five tributaries of the River Conwy, North Wales. Recently developed habitat models were applied to the data to test their ability to explain nominal spatial variance. Spatial variance accounted for between 21 and 62% of the overall variance of salmonid abundance, and habitat models explained up to 95% of the spatial variance component. Synchrony in population variation amongst sites within and between tributaries is described, and some of the factors that may influence this are discussed.