It is a nicotinic cholinoreceptor antagonist at the neuromuscular junction and a curare-like ganglioblocker.

It is a curare-form competitive anti-depolarizing muscle relaxant, used for muscle relaxation and controlled breathing under narcosis during surgical operations. It can be used for tracheal intubation.
In urethane narcotized cats (i.v.) (single pulse 3 V, 0.1 msec, 0.2 Hz, stimulation of the peripheral end of sciatic nerve): 0.1mg/kg decreases the muscle contraction amplitude for 5-10 min with slight breathing suppression. 0.2-0.3mg/kg causes a complete neuromuscular block for 5-15 min; strong breathing suppression or apnoe starting from 0.2mg/kg. 0.3mg/kg stops the breathing with lethal end. Under artificial breathing no lethality at 75mg/kg and more.

Influence of Diquine on neuromuscular synapses lability: series (15 sec series, 30 sec pause) of 0.1msec impulses of different frequency (1-30-100-200 Hz): pessimal slow-down at 0.05mg/kg at 100Hz, 0.075-0.1mg/kg at 30Hz.

On vegetative ganglia, 0.3-0.5 mg/kg stimulates the nictiating membrane on pre-ganglion cervical nerve stimulation. 1-2mg/kg slows down the neuronal transmission - two phase effect. 0.5-1mg/kg decreases the depressor reaction at vagal stimulation, no hypotension for ACh after Diquine administered at these doses. 3mg/kg completely blocks the parasympathetic ganglia for 10-15 min and causes 20-40mm Hg of arterial pressure drop for 10-30 min. In the absence of artificial breathing, 0.2-0.4 mg/kg stops breathing.

It also causes gradual fading of cardiac activity: with artificial breathing even 75 mg/kg was not lethal despite 80-120mm Hg pressure drop. No pace rate or pulse change; arterial pressure normalization after 3-4h.

Competitive curareform drug Diplacin increases, while depolarizing drugs Ditilin and Decamethonium decrease Diquine potency. 2-5 mg/kg causes no significant arterial pressure change. 0.2 mg/kg does not change nictiating membrane contraction caused by 0.02-0.025 mg/kg of cytisine. 0.0001mg/kg does not diminish ACh effect on frog rectum.

In non-narcotized rabbits (i.v.): 0.05-0.06 mg/kg causes "head drop" after 4-9 min; 0.08-0.1 mg/kg-complete muscle relaxation;0.15-0.2 mg/kg stops the breathing. With artificial ventilation spontaneous breathing recovery in 3-5 min and with muscle relaxation for 15-30 min (IC50 = 0.062 mg/kg).

In humans (i.v.): 1mg/kg causes muscle relaxation for ~10 min with some breathing suppression. 1.2-1.5 mg/kg: 15-20 min myorelaxation, for some patients 4-5 min apnoe. 1.8-2 mg/kg: complete muscle relaxation and 17-20 min apnoe; at 2 mg/kg beginning of muscle relaxation in 1.5-2 min, complete muscle relaxation and apnoe in 2.5-4 min. Gradual decurarization: after restoration of spontaneous breathing, muscle relaxation continues for 15-20 min; in 25-30 min complete recovery of muscle tonus and breathing. To prolong the action of Diquine the repeated dose must be 1.5-2 times lower. The effect is antagonized by Proserine. No effects on blood pressure, moderate tachicardia.

stable in dry state up to 100°C, store at room temperature. Solutions are stable for 1-2 days at 20°C.<br>Solutions for use: 10-³M (2mg in 3.18 ml).

highly toxic! Do not swallow nor inhale; avoid eye and skin contact.

For research use only — not intended for food, diagnostic or therapeutic use