Effects of catecholamines and adenosine derivatives given into the brain of fowls

Abstract

Summar1. Adult fowls (Gallus domesticus) with cannulae chronically implanted into the IlIrd cerebral ventricle and various other sites of the brain received microinfusions or injections of catecholamines, adenosine, 3',5'-cyclic AMP or its dibutyryl derivative. The effects of these substances on behaviour, electrocortical activity and body temperature were studied. 2. Behavioural and electrocortical sleep with fall in body temperature were obtained with intraventricular noradrenaline, a-methylnoradrenaline and isoprenaline; dopamine was ineffective. The doses required to elicit sleep were smaller than those affecting body temperature. Following mebanazine, the effects of noradrenaline were prolonged and doses of dopamine, previously ineffective, lowered body temperature and induced behavioural and electrocortical sleep.3. Noradrenaline, a-methylnoradrenaline, isoprenaline and dopamine infused into the hypothalamus induced sleep and lowered body temperature. Effective doses of noradrenaline, a-methylnoradrenaline and isoprenaline infused into the hypothalamus were one-twentieth to one-fifth those for intraventricular injection. Tachypnoea developed with isoprenaline and dopamine. Additionally with dopamine, there was deviation of the head to the contralateral side, together with repetitive jerking movements of the head. These effects were prolonged and intensified by mebanazine, whereas the involuntary movements with dopamine were greatly reduced by haloperidol. 4. Involuntary movements, but without sleep, were induced by infusing dopamine into the paleostriatum augmentatum; noradrenaline infused intothis site was ineffective. 5. In three of five fowls pretreated with aminophylline, 3',5'-cyclic AMP infused into the hypothalamus induced behavioural and electrocortical sleep; without aminophylline pretreatment, 3',5'-cyclic AMP was ineffective. Adenosine infused into the hypothalamus, following pretreatment of fowls with aminophylline, consistently induced behavioural and electrocortical sleep. Dibutyryl cyclic AMP infused into the hypothalamus of intact fowls elicited behavioural arousal, followed by bursts of electrocortical spikes (6 Hz) over both cerebral hemispheres, spikes subsequently becoming regular at 1 Hz. Clonic limb and body movements occasionally accompanied the bursts of spike activity, infrequently developing into convulsions. In fowl encephale isole preparations, in which dibutyryl cyclic AMP was infused into the hypothalamus, spike activity was confined to the ipsilateral hemisphere.

Ventral tegmental area: site through which dopamine D2‐receptor agonists evoke behavioural and electrocortical sleep in rats

“…On the contrary, drugs acting by potentiating dopaminergic transmission either acting as dopamine D1-and D2-postsynaptic agonists, as precursors (L-DOPA) or by releasing catecholamines or inhibiting catecholamine reuptake, i.e. (+)-amphetamine, produce behavioural arousal and ECoG desynchronization (see Marley & Nistico, 1972;Monti, 1982;Ongini et al, 1985;Wauquier et al, 1985;Wang et al, 1987). In addition, the activation of adenylate cyclase by cholera toxin produces behavioural stimulation and ECoG desynchronization (Nistico et al, 1976) thus reinforcing the concept that stimulation of dopamine D1-receptors (linked to adenylate cyclase) participates in the behavioural and ECoG arousal.…”

Do Central Dopamine Receptors Have a Physiological Role in Thermoregulation?

“…It also seems likely that this dopaminergic system is present in other species. Hypothalamic dopamine receptors which mediate hypothermia have been reported in the adult fowl and cat (Marley & Nistico, 1972;Quock & Gale, 1974). Studies on rostral hypothalamic neurones sensitive to peripheral temperature changes have failed to reveal any consistent relationship between response to temperature and to acetylcholine, noradrenaline or 5-hydroxytryptamine applied iontophoretically (Jell, 1974).…”

Multiple components of the A1 adenosine receptor-adenylate cyclase system are regulated in rat cerebral cortex by chronic caffeine ingestion.

“…The purine produces marked sedation (24,(39)(40)(41) and anticonvulsant activity (40). In addition, administration of adenosine analogues to animals produces analgesia (24,42,43).…”