sincalide and Anxiety-Disorders

It has been suggested that cholecystokinin (CCK), a gut-brain peptide found in high concentrations in the mammalian brain, might be implicated in the neurobiology of anxiety and panic disorder. The administration of CCK tetrapeptide induced panic attacks analogous to spontaneous ones in patients suffering from panic disorder and to a lesser degree in healthy volunteers. In animal models of anxiety, the pretreatment with CCK agonists and antagonists produced, respectively, anxiogenic- and anxiolytic-like action on the exploratory paradigms. On the other hand, CCK could also play a role in the pathophysiology of schizophrenia. The administration of CCK agonists (caerulein, CCK-8s) to rodents results in behavioural effects analogous to those of antipsychotic drugs. However, CCK agonists lack any activity in rodent behavioural models to reveal antipsychotic drugs. A significant reduction of CCK concentration and CCK receptors has been shown in cortical and limbic structures of patients suffering from schizophrenia. Nevertheless, administration of CCK agonists to these patients does not effect their symptoms. Two major conclusions should be drawn: first, CCK is involved in the neurobiology of anxiety; second, changes in the CCK system in schizophrenia could be linked to a cortical neurodegeneration related to this disease.

Topics: Animals; Anxiety Disorders; Ceruletide; Cholecystokinin; Humans; Neurotransmitter Agents; Receptors, Cholecystokinin; Schizophrenia; Sincalide

Topics: Animals; Anxiety; Anxiety Disorders; Cholecystokinin; gamma-Aminobutyric Acid; Humans; Sincalide; Tetragastrin

Type 5 adenylyl cyclase (AC5) is highly concentrated in the dorsal striatum and nucleus accumbens (NAc), two brain areas which have been implicated in motor function, reward, and emotion. Here we demonstrate that mice lacking AC5 (AC5-/-) display strong reductions in anxiety-like behavior in several paradigms. This anxiolytic behavior in AC5-/- mice was reduced by the D(1) receptor antagonist SCH23390 and enhanced by the D(1) dopamine receptor agonist, dihydrexidine (DHX). DHX-stimulated c-fos induction in AC5-/- mice was blunted in the dorso-lateral striatum, but it was overactivated in the dorso-medial striatum and NAc. The siRNA-mediated inhibition of AC5 levels within the NAc was sufficient to produce an anxiolytic-like response. Microarray and RT-PCR analyses revealed an up-regulation of prodynorphin and down-regulation of cholecystokinin (CCK) in the NAc of AC5-/- mice. Administration of nor-binaltorphimine (a kappa opioid receptor antagonist) or CCK-8s (a CCK receptor agonist) reversed the anxiolytic-like behavior exhibited by AC5-/- mutants. Taken together, these results suggest an essential role of AC5 in the NAc for maintaining normal levels of anxiety.

Topics: Adenylyl Cyclases; Animals; Anxiety Disorders; Benzazepines; Cholecystokinin; Dopamine; Dopamine Agonists; Dopamine Antagonists; Down-Regulation; Enkephalins; Gene Expression Regulation, Enzymologic; Isoenzymes; Mice; Mice, Knockout; Narcotic Antagonists; Nucleus Accumbens; Phenanthridines; Protein Precursors; Receptors, Dopamine D1; Receptors, Opioid, kappa; RNA, Small Interfering; Sincalide; Up-Regulation

A total of 31 intravenous injections of the tetrapeptide cholecystokinin (30-33) were carried out in ten healthy subjects. In seven subjects, cholecystokinin-4 provoked a short-lasting (one to four minutes) panic-like attack (an intense unexplainable fear) at doses between 20 and 100 micrograms. In the other three subjects, doses of 80 to 100 micrograms induced severe anxiety, but no panic-like attack. All subjects experienced severe gastrointestinal symptoms. Pretreatment with lorazepam, but not with meprobamate or naloxone, prevented the psychic effects of cholecystokinin-4 in subjects who had experienced a panic-like attack with the same dose of this peptide. Following the peptide injection, levels of plasma free catecholamines, lactate, and glucose were unchanged, whereas levels of plasma cortisol and prolactin were increased. The intravenous injection of the sulfated cholecystokinin octapeptide (26-33) in two subjects (doses of 35 and 40 micrograms, respectively) produced severe gastrointestinal symptoms, but failed to induce any anxiety or panic-like attacks. These preliminary findings suggest that cholecystokinin-4 may have a panic-inducing effect. It remains to be established if this peptide exerts this effect via a direct activation of central cholecystokinin receptors.

Topics: Adult; Anxiety Disorders; Blood Pressure; Brain; Cholecystokinin; Dopamine; Epinephrine; Fear; Female; Heart Rate; Humans; Hydrocortisone; Injections, Intravenous; Male; Norepinephrine; Panic; Peptide Fragments; Prolactin; Receptors, Cholecystokinin; Sincalide