Related Experiment Video
Updated: Jul 30, 2026

Controlled Cortical Impact Model for Traumatic Brain Injury
Published on: August 5, 2014
Head injury: clonidine decreases plasma catecholamines
D Payen1, L Quintin, P Plaisance
1Département d'Anesthésie-Réanimation, Hôpital Universitaire Lariboisière, Paris, France.
Abstract:
Seven patients who had suffered head injury 3 to 5 days before the study was undertaken received clonidine (2.5 micrograms/kg iv over 10 min). This resulted in a reduction of plasma norepinephrine (p less than .05) and in normalization of plasma epinephrine (p less than .05). Neither common carotid blood flow nor diastolic blood flow as index of global cerebral perfusion as measured by pulsed Doppler changed. The reduction of sympathetic overactivity, probably due to the specific action of clonidine on alpha 2-adrenoceptors within the rostral ventrolateral medulla, may be of interest in the management of head injury because of the maintenance of cephalic hemodynamics.
More Related Videos
Related Concept Videos
Drugs Acting on Autonomic Ganglia: Blockers
Adrenergic Agonists: Indirect-Acting Agents
One mechanism involves depleting stored catecholamines by displacing them from synaptic vesicles. These agents, known as "displacers," are transported into vesicles at the expense of noradrenaline. Examples include amphetamine and tyramine, which lack a catechol moiety, resulting in prolonged action, improved oral bioavailability, and...
Adrenergic Agonists: Therapeutic Uses
Emergency and Intensive Care Unit (ICU) applications: Pressor agents increase blood pressure, heart rate, and contractility in shock and organ failure situations. Dopamine can induce vasodilation and stimulate adrenoceptors. Endogenous catecholamines are effective in treating cardiogenic shock. α2-agonists like clonidine can reverse anesthesia-induced hypertension.
Allergies and anaphylaxis:...
Adrenergic Antagonists: Pharmacological Actions of β-Receptor Blockers
Drugs Affecting Neurotransmitter Release or Uptake
Cardiopulmonary Resuscitation IV: Pharmacological Management

