Alterations of bromocriptine-induced penile erection by chronic lithium in rats

Aspirin for treatment of lithium-associated sexual dysfunction in men: randomized double-blind placebo-controlled study

OBJECTIVES

The aim of the present study was to assess the effect of aspirin on lithium-related sexual dysfunction in men with stable bipolar affective disorder (BAD).

METHODS

In a randomized, double-blind, placebo-controlled study, 32 men with stable BAD who had been on lithium maintenance therapy randomly received aspirin (240 mg/day) or placebo for six weeks. The International Index for Erectile Function (IIEF) was used to assess sexual symptoms at baseline, Week 3, and Week 6. Depressive and mania symptoms and plasma lithium concentrations were assessed at baseline and Week 6. Side effects were assessed using a checklist.

RESULTS

Thirty patients (15/group) completed the study. Baseline and endpoint lithium concentrations and mania and depressive symptoms did not differ significantly between the two groups. Significant effects of time × treatment interaction were observed for total score [Greenhouse-Geisser: F(1.410,39.466) = 6.084, p = 0.010] and erectile function [Greenhouse-Geisser: F(1.629,45.602) = 7.250, p = 0.003]. By Week 6, patients in the aspirin group showed significantly greater improvement in the total (63.9% improvement from the baseline) and erectile function domain (85.4% improvement from the baseline) scores than the placebo group (14.4% and 19.7% improvement from the baseline, p-values = 0.002 and 0.001, respectively). By Week 6, 12 (80%) patients in the aspirin group and three (20%) patients in the placebo group met the criteria of minimal clinically important change [χ(2) (1) = 10.800, p = 0.001]. Other IIEF domains also showed significant improvement at the end of the trial. The frequency of side effects was similar between the two groups.

CONCLUSION

Aspirin effectively improves lithium-related sexual dysfunction in men with stable BAD.

Hormesis and medicine

Evidence is presented which supports the conclusion that the hormetic dose-response model is the most common and fundamental in the biological and biomedical sciences, being highly generalizable across biological model, endpoint measured and chemical class and physical agent. The paper provides a broad spectrum of applications of the hormesis concept for clinical medicine including anxiety, seizure, memory, stroke, cancer chemotherapy, dermatological processes such as hair growth, osteoporosis, ocular diseases, including retinal detachment, statin effects on cardiovascular function and tumour development, benign prostate enlargement, male sexual behaviours/dysfunctions, and prion diseases.

Effects of lithium carbonate on apomorphine-induced sniffing behaviour in rats

Effects of lithium carbonate (Li2CO3) on sniffing induced by apomorphine have been tested in rats. Intraperitoneal administration of different doses of apomorphine (0.25, 0.5 and 1 mg/kg) induced a dose-dependent sniffing response. Chronic Li2CO3 exposure (0.1% in drinking water for 30-35 days) but not acute administration of the drug (320 mg/kg, intraperitoneally) decreased the response of apomorphine. The response to chronic Li2CO3 exposure was observed when apomorphine was injected 60 min., 24 hr or 72 hr after Li2CO3withdrawal, with maximum effect observed when the drug was administered 72 hr after withdrawal of Li2CO3. Blockade of sniffing induced by apomorphine by the D1 dopamine receptor antagonist, SCH23390 (0.005 mg/kg, intraperitoneally) or the D2 dopamine receptor antagonist, sulpiride (25 mg/kg, intraperitoneally) was not increased in acute Li2CO3-treated animals. In animals which were treated chronically with Li2CO3, the blockade of apomorphine response by sulpiride but not by SCH23390 was potentiated. It is concluded that chronic treatment of animals with Li2CO3 is able to alter D2 dopamine receptors response.

Effects of chronic lithium on ototoxicity induced by gentamicin and amikacin in guinea-pigs

The effects of chronic lithium co-therapy on the expression of gentamicin and amikacin ototoxicity were tested in guinea-pigs. Intramuscular injection of different doses of gentamicin (5, 10 mg/kg/day) and amikacin (150, 300 mg/kg/day) for three weeks, induced hearing loss consistent with the established pattern of aminoglycoside ototoxicity. Lithium salts remains one of the most widely used treatment for depressive illness. Administration of lithium chloride (600 mg/l, 35 days) in drinking water changed auditory brainstem response in a time-dependent manner. Pretreatment of animals with lithium chloride after seven days induced significant alterations in wave latency and interval. The present study assesses the protective effects of chronic lithium on gentamicin-induced ototoxicity in guinea pig. The results suggest that duration of lithium administration may be involved in auditory brainstem response changes and the observations could be accounted for, at least partially, by lithium- and aminoglycosides-induced perturbations of the phosphoinositide cascade within the inner ear.

The effect of acute lithium and rubidium pretreatment on apomorphine-induced pecking in pigeons

The effects of different doses of lithium (5-320 mg/kg intramuscularly) and rubidium (0.25 32 mg/kg intramuscularly) on apomorphine-induced pecking were investigated in pigeons. These two cations did not induce pecking by itself. Intramuscular administration of apomorphine (a mixed D1/D2 dopamine receptors agonist, 0.1-1.6 mg/kg) induced pecking in a dose-dependent manner. SCH 23390 (D1 dopamine receptor antagonist, 0.02-0.08 mg/kg) and sulpiride (D2 dopamine receptor antagonist, 25-100 mg/kg) decreased apomorphine-induced pecking dose-dependently. Combination of SCH 23390 (0.04 mg/kg) with sulpiride (50 mg/kg) caused a stronger inhibitory effect on apomorphine response. This indicates that both D1 and D2 dopamine receptors are involved in apomorphine-induced pecking. The response induced by apomorphine (0.2-0.8 mg/kg) was decreased in animals pretreated with lithium and rubidium. In these conditions, SCH 23390 and sulpiride produced a larger inhibitory effect on the apomorphine response, suggesting that acute lithium and rubidium pretreatment inhibit pecking by interfering with dopaminergic mechanisms.

Alterations of physostigmine-induced yawning by chronic lithium administration in rats

The effect of chronic lithium pretreatment on physostigmine-induced yawning was investigated in male rats. Intraperitoneal administration of physostigmine to rats induced yawning in a biphasic manner. However the maximum response was obtained by 0.2 mg/kg of the drug. Intracerebroventricular administrations of a putative M1 and M2 muscarinic receptor antagonists, pirenzepine and methoctramine decreased physostigmine-induced yawning. Intraperitoneal administration of a non-selective muscarinic receptor antagonist, atropine, also decreased the physostigmine-induced yawning significantly. Chronic lithium pretreatment (30 days) reduced yawning induced by physostigmine. The inhibitory effect of pirenzepine, methoctramine and atropine on physostigmine-induced yawning increased in rats pretreated with chronic lithium. These findings indicate that yawning is induced by a central cholinergic mechanism and that chronic pretreatment of lithium may interact with the cholinergic-induced behaviour.

Effects of lead exposure on bromocriptine-induced penile erection in rats

In the present work we have studied the effects of lead exposure on penile erection induced by bromocriptine. Intraperitoneal injection of bromocriptine (2, 3, 4 and 8 mg/kg) induced dose-related penile erection in rats. Maximum response was observed with 4 mg/kg of the drug. Lead exposure (as Pb-acetate in drinking water) for periods of 7, 14, 21 and 28 days decreased the bromocriptine-induced penile erection response. Higher concentrations of lead (0.05%) were shown to cause a more prominent decrease of penile erection. The same procedure for lead administration did not significantly alter penile erection induced by physostigmine (0.1 and 0.3 mg/kg, intraperitoneally). In a series of experiments, blood lead concentrations were measured 7 and 21 days after lead exposure. Significant increases of lead concentrations were found after lead exposure. It is concluded that lead can influence bromocriptine-induced penile erection.