The temporal course of yawning behavior elicited by increasing doses of apomorphine (APO), from 0.01 to 10 mg/kg, was studied experimentally in adult albino rats. In the higher dose range a great prolongation of drug induced yawning latency is observed. This result is explainable by postulating differences in sensitivity of two sets of dopaminergic (DA) receptors: low threshold presynaptic DA r...

In the present study, the effects of intra-cerebral hippocampus (CA1) injections of apomorphine D1, D2-like receptors agonists on morphine-induced place preference in male Wistar rats have been investigated. Subcutaneous administration of different dose of morphine sulphate (1, 3, 6 and 9 mg/kg) produced a dose-dependent conditioned place preference (CPP). Intra-cerebral hippocampus (CA1) admin...

Yawning is a reflex or event that is not fully understood. It is controlled by many neurotransmitters and neuropeptides and can be induced pharmacologically by cholinergic or dopaminergic agonists. Amongst their many actions, cannabinoids acting on cannabinoid (CB(1) or CB(2)) receptors can alter cholinergic and/or dopaminergic activity. This study examined the effects of Delta(8)-tetrahydrocan...

Synaptotagmin 7 (Syt 7) is a Ca2+ sensor implicated in the regulation of membrane fusion in vesicular transport, but its precise role in neurons is still a matter of controversy. Dopaminergic drugs have been shown to modulate its expression in the striatum. Here we investigate whether dopamine receptor agonist-up-regulation of Syt 7 mRNA is specifically involved in the pathophysiological adapta...

Electrophysiological studies have shown that chronic treatment with haloperidol causes depolarization block (DB) of dopamine cells in anesthetized and paralyzed rats. It has been proposed that the emergence of DB underlies the therapeutic and side effects of this drug. However, the relevance of DB to the clinical actions of haloperidol has been questioned on the grounds that chronic drug-induce...

The probable roles of Acetylcholine (Ach) and Dopamine (DA) in the modulation of instinctual behaviors of feeding and hoarding (HS), as also the body weight and vaginal cyclicity (EI), were studied by instillation of Atropine (Ach antagonist), Haloperidol (DA antagonist) and Apomorphine (DA agonist) in the dorsal hippocampus of nonpregnant female rats. It was observed that the HS was significan...

Rats of sham repeated transcranial magnetic stimulation (rTMS) group, kept in noisy room and transiently immobilized (5 min) for 12 consecutive days, showed similar inhibition of body weight gain, increase in exploratory locomotor activity, and elevation of motor response to apomorphine as rats undergoing magnetic stimulation of the brain, and had only slightly lower response in apomorphine ste...