Biomaterial Database

Effects of pretreatment with 6-hydroxydopamine or noradrenergic receptor blockers on the clonidine-induced distruption of conditioned avoidance responding. 1979

M Hawkins, and J M Monti

The effects of clonidine were assessed on conditioned avoidance responses (CAR) in control, 6-hydroxy-dopamine (6-OHDA)- and vehicle-treated rats, using a shuttle box device. Clonidine (100--400 micrograms/kg) produced a significant decrease of CAR in control and vehicle-treated animals. On the other hand, avoidance responding was only slightly inhibited in the 6-OHDA-lesioned rats. Pretreatment with the alpha-adrenergic blocking drugs yohimbine or phentolamine (1--8 mg/kg) prevented the CAR disrupting effects of clonidine. When animals were pretreated with the beta-adrenergic blocking agent propranolol (1--8 mg/kg) the ensuing injection of clonidine caused a greater CAR depression. Our results further support the hypothesis relating the conditioned performance depression observed after clonidine to the activation of a presynaptic negative feedback mechanism mediated by alpha-adrenoceptors. It is also suggested that propranolol increases the clonidine inhibition through the blockade of a positive feedback mechanism dependent on the activation of presynaptic beta-receptors.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D010646	Phentolamine	A nonselective alpha-adrenergic antagonist. It is used in the treatment of hypertension and hypertensive emergencies, pheochromocytoma, vasospasm of RAYNAUD DISEASE and frostbite, clonidine withdrawal syndrome, impotence, and peripheral vascular disease.	Fentolamin,Phentolamine Mesilate,Phentolamine Mesylate,Phentolamine Methanesulfonate,Phentolamine Mono-hydrochloride,Regitine,Regityn,Rogitine,Z-Max,Mesilate, Phentolamine,Mesylate, Phentolamine,Methanesulfonate, Phentolamine,Mono-hydrochloride, Phentolamine,Phentolamine Mono hydrochloride
D011433	Propranolol	A widely used non-cardioselective beta-adrenergic antagonist. Propranolol has been used for MYOCARDIAL INFARCTION; ARRHYTHMIA; ANGINA PECTORIS; HYPERTENSION; HYPERTHYROIDISM; MIGRAINE; PHEOCHROMOCYTOMA; and ANXIETY but adverse effects instigate replacement by newer drugs.	Dexpropranolol,AY-20694,Anaprilin,Anapriline,Avlocardyl,Betadren,Dociton,Inderal,Obsidan,Obzidan,Propanolol,Propranolol Hydrochloride,Rexigen,AY 20694,AY20694,Hydrochloride, Propranolol
D003000	Clonidine	An imidazoline sympatholytic agent that stimulates ALPHA-2 ADRENERGIC RECEPTORS and central IMIDAZOLINE RECEPTORS. It is commonly used in the management of HYPERTENSION.	Catapres,Catapresan,Catapressan,Chlophazolin,Clofelin,Clofenil,Clonidine Dihydrochloride,Clonidine Hydrochloride,Clonidine Monohydrobromide,Clonidine Monohydrochloride,Clopheline,Dixarit,Gemiton,Hemiton,Isoglaucon,Klofelin,Klofenil,M-5041T,ST-155,Dihydrochloride, Clonidine,Hydrochloride, Clonidine,M 5041T,M5041T,Monohydrobromide, Clonidine,Monohydrochloride, Clonidine,ST 155,ST155
D004305	Dose-Response Relationship, Drug	The relationship between the dose of an administered drug and the response of the organism to the drug.	Dose Response Relationship, Drug,Dose-Response Relationships, Drug,Drug Dose-Response Relationship,Drug Dose-Response Relationships,Relationship, Drug Dose-Response,Relationships, Drug Dose-Response
D004347	Drug Interactions	The action of a drug that may affect the activity, metabolism, or toxicity of another drug.	Drug Interaction,Interaction, Drug,Interactions, Drug
D006892	Hydroxydopamines	Dopamines with a hydroxy group substituted in one or more positions.	Hydroxydopamine
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001362	Avoidance Learning	A response to a cue that is instrumental in avoiding a noxious experience.	Aversion Behavior,Aversion Learning,Aversive Behavior,Aversive Learning,Avoidance Behavior,Aversion Behaviors,Aversive Behaviors,Avoidance Behaviors,Behavior, Aversion,Behavior, Aversive,Behavior, Avoidance,Behaviors, Aversion,Behaviors, Aversive,Behaviors, Avoidance,Learning, Aversion,Learning, Aversive,Learning, Avoidance
D013565	Sympatholytics	Drugs that inhibit the actions of the sympathetic nervous system by any mechanism. The most common of these are the ADRENERGIC ANTAGONISTS and drugs that deplete norepinephrine or reduce the release of transmitters from adrenergic postganglionic terminals (see ADRENERGIC AGENTS). Drugs that act in the central nervous system to reduce sympathetic activity (e.g., centrally acting alpha-2 adrenergic agonists, see ADRENERGIC ALPHA-AGONISTS) are included here.	Sympathetic-Blocking Agents,Sympatholytic,Sympatholytic Agent,Sympatholytic Drug,Sympatholytic Agents,Sympatholytic Drugs,Sympatholytic Effect,Sympatholytic Effects,Agent, Sympatholytic,Agents, Sympathetic-Blocking,Agents, Sympatholytic,Drug, Sympatholytic,Drugs, Sympatholytic,Effect, Sympatholytic,Effects, Sympatholytic,Sympathetic Blocking Agents