Search results for "pine"

ChemInform Abstract: The Reaction of 2,4,5,6-Tetraaminopyrimidine with Chalcones.

2010

The reaction of the tetraaminopyrimidine 1 with the chalcones 2a-f yields, in the presence of catalytic amounts of acetic acid, the 1H-pyrimido[4,5-b][1,4]diazepine derivatives 3a-f. The cyclization process consists of a condensation reaction and a Michael type addition.

Day/night serotonin levels in the pineal gland of male BALB/c mice with melatonin deficiency

1988

Abstract. Studies from another laboratory have shown that several strains of laboratory mice have a genetic defect for melatonin synthesis. In non-deficient species, melatonin synthesis undergoes a typical, β-adrenergically regulated day/night rhythm with low melatonin levels during daytime and high levels at night, the precursor serotonin showing an inverse behaviour. This study examines whether a day/night rhythm of pineal serotonin levels exists in melatonin-deficient male BALB/c mice. Mice kept under a lighting schedule of 12 h light (lights on at 07.00 h) and 12 h dark were killed at 13.00 and 01.00 h, respectively. Serotonin amounted to 12-15 ng/pineal and did not show regular day/nig…

Effects of electrical stimulation of the superior cervical ganglia on the number of ?synaptic? ribbons and the activity of melatonin-forming enzymes …

1989

Melatonin metabolism in the mammalian pineal gland is under the clear influence of sympathetic fibers originating in the superior cervical ganglia (SCG). Previous studies suggested that pineal "synaptic" ribbons (SR) as well are regulated by the gland's sympathetic innervation. To gain more insight into the mechanisms involved, we examined the effects of sympathetic stimulation on SR number and on the activity of melatonin forming enzymes, serotonin N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT). The SCG in adult male rats were stimulated electrically during daytime for either 15 or 120 min. Immediately following stimulation, the glands were removed and processed fo…

The pineal complex in Roman high avoidance and Roman low avoidance rats.

1990

Previous studies have shown that the pineal gland of Roman high avoidance (RHA/Verh) rats is larger than that of Roman low avoidance rats (RLA/Verh). In the present study measurement of enzyme activities (serotonin-N-acetyl-transferase, hydroxyindole-O-methyltransferase) revealed that pineals of RHA/Verh rats are twice as active in melatonin production than pineals of RLA/Verh rats. Indoleamine content was also higher in RHA/Verh rats, whereas noradrenaline content was the same in both lines. When values were expressed per mg protein, these differences disappeared except for N-acetyl-serotonin and noradrenaline which were higher or lower in RHA/Verh rats, respectively. Both lines had higher…

Melatonin formation in different parts of the guinea-pig pineal complex as assessed over 24 hours.

1985

There is morphological evidence that the pineal gland is not a uniformly built organ but rather a complex. In the guinea-pig the gland is 6--7 mm in length and dumbbell-shaped, the proximal part coming into intimate contact with central commissural fibres. The aim of the present 24-hour study was to examine in male guinea-pigs whether the proximal, intermediate and distal areas of the gland are involved in melatonin formation and to compare their rhythmicities. Levels of melatonin in serum and the whole pineal gland as assessed by RIA show day/night ratios of 1 : 1.25 and 1 : 3.3, respectively. Serotonin N-acetyltransferase activity was found to exhibit ratios of 1 : 1.75 (Experiment I) and…

Response of pineal serotonin N-acetyltransferase activity in male guinea pigs exposed to light pulses at night.

1988

Serotonin N-acetyltransferase (NAT), which is crucial for the formation of melatonin, undergoes a typical day/night rhythm in the pineal gland with low levels during daytime and high levels at night. Short pulses of light given at night have been shown to rapidly depress NAT activity in some species, but not in others, the reasons for this difference being unclear. As diurnality and nocturnality of the experimental animals may play a role and since diurnally active animals have been little investigated in this respect, in the present study the diurnally active guinea pig was investigated. Male guinea pigs kept under a lighting regimen of LD 12:12 (lights off at 1700 hrs) were killed between…

Neuropeptide Y effects on pineal melatonin synthesis in the rat

1987

Neuropeptide Y (NPY)-like immunoreactivity is present in the rodent pineal gland. To elucidate possible effects on pineal melatonin synthesis NPY (5 nmol/kg body wt.) was injected into the common carotid artery of male rats. Activities of the melatonin biosynthetic enzymes, serotonin N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT) were determined by means of radioenzymatic methods. Intact light-exposed animal showed increased NAT activity at day- and at nighttime. Blinded animals showed a more than 10-fold reduction of NAT activity after nocturnal NPY injections. HIOMT activity was only slightly influenced at either time. These results are discussed in terms of the p…

Effects of an earth-strength magnetic field on pineal melatonin synthesis in pigeons

1987

Community dimensions and emotions in the era of COVID-19

2021

Abstract Following an ecological perspective, reactions to a disaster—such as the COVID‐19 pandemic—should be analysed in the interdependence between individual and community dimensions. The present study aims to analyse individual emotional dimensions (anxiety, joy, fear or depressive feelings) and their community dimensions (connectedness, emotional sharing and solidarity) with a longitudinal approach among university students from Italian universities. Participants were 746 university students at t1 (during the lockdown) and 361 at t2 (after the lockdown) recruited in six Italian universities from different areas of Italy. Comparing emotional dimensions in the two times, t2 is characteri…

The Effect of Tyramine, Noradrenaline, and Angiotensin on the Blood Pressure in Hypertensive Patients with Aldosteronism and Low Plasma Renin

1970

The reactivity to the pressor action of tyramine, noradrenaline, and angiotensin was determined in 9 patients with hypertension, aldosteronism and low plasma renin concentration (4 patients with solitary adrenal adenomas, 3 patients with nodular adrenal hyperplasia, 2 patients with unknown adrenal status). In 7 patients tests were repeated following unilateral or subtotal adrenalectomy respectively. For comparison, 5 patients with phaeochromocytoma, 10 patients with benign essential hypertension, and 12 normotensive control subjects were studied. — In the hypertensive patients with aldosteronism and low plasma renin, responsiveness to tyramine was significantly reduced. In contrast, pressor…