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Introduction and Development: Cannabis and derivatives induce complex effects on anxiety in humans and experimental animals. At low doses, cannabinoid agonists seem to exert anxiolytic actions, while at high doses anxiety and panic estates are often reported. Diverse animal models confirm this particular biphasic profile; however, the underlying neurobiological mechanisms have not been completely elucidated. The anxiogenic-like behavioral phenotype observed following both pharmacological and genetic blockade of cannabinoid CB1 receptors, together with the abundant expression of cannabinoid receptors within brain areas particularly involved in emotional control, such as amygdala, hippocampus and cortex, are among the numerous evidences that account for the participation of the endocannabinoid system in the regulation of anxiety states. Moreover, blockade of endogenous cannabinoid ligands deactivation has been reported to induce anxiolytic-like responses., Conclusions: Taken together, present data reinforce the involvement of the endocannabinoid system in the control of emotional homeostasis and further suggest the pharmacological manipulation of the endocannabinoid system as a potential therapeutic tool in the management of anxiety-related disorders.

Carbon monoxide is considered to be a major factor contaminating earth's atmosphere. The main sources producing this contamination are cars using gasoline or diesel fuel and industrial processes using carbon compounds; these two are responsible for 80% of carbon monoxide being emitted to the atmosphere. This substance has a well-known toxic effect on human beings and its acute poisonous effects (including death) have been widely studied; however, its long-term chronic effects are still not known. During the last few years, experimental research on animals and studies of human epidemiology have established the relationship between chronic exposure to low and middle levels of carbon monoxide in breathable air and adverse effects on human health, especially on organs consuming large amounts of oxygen such as the heart and brain. Harmful cardiovascular and neuropsychological effects have been documented in carbon monoxide concentration in air of less than 25 ppm and in carboxyhaemoglobin levels in blood of less than 10%. The main cardiac damage described to date has been high blood pressure, cardiac arrhythm and electrocardiograph signs of ischemia. Lack of memory, attention, concentration and Parkinson-type altered movement are the neuropsychological changes most frequently associated with chronic exposure to low levels of carbon monoxide and carboxyhaemoglobin.

The effects of changes in brain serotonin content after injections of p-chlorophenylalanine (p-CPA), L-5-hydroxytryptophan (L-5HTP) and 5-6-dihydroxytryptamine (5-6DHT) on the mean arterial pressure (MAP), plasma renin activity (PRA) and peripheral levels of atrial natriuretic peptide (ANP) have been studied in normal and hypertensive (2K:1C model) male Wistar rats. The p-CPA (250 mg/kg) and L-5HTP (200 mg/kg) were injected i.p., while 5-6 DHT (15 micrograms/animal in 10 mu/animal vehicle) was injected into lateral brain ventricles. The effects were studied 24 h after the p-CPA injection, 2 h after L-5HTP and 10 or 20 days after 5-6DHT administration. The fall in brain serotonin produced by p-CPA and 5-6DHT did not modify the MAP values in the normal and hypertensive rat model, whereas the increase induced after L-5HTP injection only caused a slight decrease in arterial pressure in normotensive animals. The ARP experimented remarkable rises in the normal and hypertensive rats, these values increasing after L-5HTP and falling after p-CPA and 5-6 DHT injections. Similar changes are detected in the normal group after administration of these substances related to serotoninergic brain activity. The ANP levels rose after renal artery constriction, and they are not affected by the above mentioned substances. Only p-CPA and 5-6DHT reduced a low decrease in the ANP levels 10 days after their administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Sodium diphenylhydantoin (DFH-Na) is the drug of choice to control convulsive seizure disorders. Beneficial as well as adverse effects of DFH-Na have been reported to occur since 1938. Thus, the present article deals with the effect that 2.5, 5, 10, 15, 20 and 100 mg/kg/day (2.5, 5, 10, 15, 20 and 100) might cause on Cerebrum (C), Cerebellum (Cb) and liver (L) DNA [DNA] and Protein [Pr] concentration. Our results showed that: 1) DNA-C-14 (15, 20 and 100) were found decreased when compared to control (p less than 0.001) and [DNA]-C-30 (15, 20 and 100) as well (p less than 0.001). [Pr]-C-7, 14, 30 (2.5, 5, 10, 15, 20 and 100) showed no statistically important differences. 2) [DNA]-Cb-14 (15 and 20) were found lower than control (p less than 0.05) and [DNA]-Cb-30 (15 and 20) as well (p less than 0.05). [Pr]-Cb-14,30 (100) was found decreased (p less than 0.05). 3) [DNA]-L-14 (10, 15, 20 and 100) was found decreased when compared to control (p less than 0.001) and [DNA]-L-30 (10, 15, 20 and 100) as well (p less than 0.001). [Pr]-L-7, 14 and 30 (2.5, 5, 10, 15, 20 and 100) were found lower than control (p less than 0.05). A bimodal pattern of [DNA] of C. Cb and L was demonstrated to occur with i.p. injected DFH-Na.

The effect of a type A MAO inhibitor, clorgyline, injected alone or with alpha-methyl-p-tyrosine (aMpT) on the plasmatic corticosterone levels estimated at 9 a.m. and 5 p.m. has been studied in male Wistar rats. The clorgyline injected alone produced significant decreases in corticosterone values, especially at 5 p.m., determining a variation lack between the morning and the afternoon levels. When alpha-MpT is associated to IMAO, increases at both points of the day considered in this experiment take place. The amount of NA and 5-HT in the brain was also estimated; clorgyline high increases in Na and 5-HT contents, 5-HT; aMpT reduces the effect of clorgyline, especially as regards content. The results are discussed in relation to this highly specific MAO inhibitor and with the role of these amines as modulators of ACTH secretion. In view of the changes introduced by the aMpT injection, the modifications produced by clorgyline alone are related to NA, but to 5-HT, when the NA synthesis has been interrupted by the tyrosine hydroxylase inhibitor.