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

Abstract

In the present study, the effects of chronic lithium pre-treatment (30 days) on penile erection (PE) induced by bromocriptine were investigated in rats. Intraperitoneal administration of the dopamine receptor agonist, bromocriptine (4-32 mg/kg) induced PE in a biphasic manner. The maximum response was obtained with 8 mg/kg of bromocriptine and the effect was decreased with increasing doses of the drug from 8 to 32 mg/kg. When animals were pre-treated with different doses of the D-1 dopamine receptor antagonist, SCH 23390, or the D-2 dopamine receptor antagonist, sulpiride, the PE response was decreased. The response induced by bromocriptine (4-32mg/kg) was reduced in animals pre-treated with chronic lithium. SCH 23390 did not produce a larger inhibitory effect on the bromocriptine response in animals pre-treated with chronic lithium, but the inhibitory effect of sulpiride was increased in this condition. It is concluded that chronic lithium treatment may alter the D-1/D-2 receptor activity and inhibit bromocriptine-induced PE.

Effects of Different Periods of Lithium Pretreatment and Aminoglycoside Antibiotics on Apomorphine‐Induced Yawning in Rats

“…In addition, lithium can inhibit the effects of a number of adenylyl cyclase-linked receptors such as dopamine receptors (Kebabian & Calne 1979;Ebstein et al 1980;Braun & Chase 1986). Therefore the inhibitory effects of lithium may be due to post-receptor mechanism interactions, which was also reported in our previous works (Sharifzadeh et al 1996(Sharifzadeh et al , 1997(Sharifzadeh et al & 1998. The maximum inhibitory effect of lithium was observed after 14 days.…”

“…One of the major findings of the present study is that the yawning response induced by apomorphine was decreased in animals pretreated with lithium for 7, 14 and 21 days. Our previous investigations have also shown that lithium can decrease penile erection induced by activation of the dopaminergic system (Dehpour et al 1995;Sharifzadeh et al 1996) and yawning response induced by cholonergic activation (Sharifzadeh et al 1997). It has been reported that lithium causes depletion of cytoplasmic inositol and phosphoinositide turnover (Hallcher & Sherman 1980;Del-Rio et al 1998), which could interfere with the re-synthesis of phosphatidyl inositol bisphosphate, thus influencing the signaling mechanisms operating through the phosphoinositide system.…”

“…Lithium has also been shown to interact with phosphoinositide metabolism by inhibiting of inositol monophosphatase (Berridge et al 1982;Nahorski et al 1991). Our previous works have shown that lithium can alter some behaviours induced by dopaminergic and cholinergic agents (Dehpour et al 1995;Sharifzadeh et al 1996Sharifzadeh et al & 1997. The present study was carried out to clarify the interactive effects of intracerebroventricular administration of aminoglycoside antibiotics with different durations of lithium pretreatment on apomorphine-induced yawning in rats.…”

Alterations of Physostigmine‐Induced Yawning by Chronic Lithium Administration in Rats

“…The major finding of the present study is the yawning response induced by physostigmine was decreased in animals pretreated with chronic lithium. Our previous investigations have also shown that chronic lithium can decrease penile erection induced by activation of dopaminergic system (Dehpour et al 1995 ;Sharifzadeh et al 1996).…”

Effects of Chronic Lithium on Ototoxicity Induced by Gentamicin and Amikacin in Guinea‐Pigs

“…Our previous works have shown that chronic lithium can alter responses that are mediated by phosphoinositides pathway (Dehpour et a/. 1995;Sharifzadeh et a/. 1996Sharifzadeh et a/.…”