Drugs that act on ionotropic receptors

01

Drugs that act on

ionotropic receptors

Domina Petric, MD

03

Nicotine

nAChR are very important in many cognitive processes.

• Rewarding effect of nicotine is

associated with ventral tegmental area

(VTA) where there are nAChR on

dopaminergic neurons.

Abstinence

syndromeirritability

insomnia

Nicotine is

very

addictive.

nAChR that contain α4β2

component are especially

important for the rewarding

effect of nicotine.

DEFAULT STYLES 04

Nicotine

– Partial agonists of α4β2

nAChR: citizine and

varenicline.

– Bupropion!

– Cognitive and behavioral

therapy.

05

Treatment

Benzodiazepines and

barbiturates• Benzodiazepines are safer than

barbiturates.

• Physical addiction on benzodiazepines

is very common.

• Abstinence syndrome: irritability,

insomnia, phonofobia, photofobia,

depression, muscle cramps and

convulsions.

Benzodiazepines and

barbiturates

Benzodiazepines are positive modulatorsof GABAA receptors.

Alcohol

Alcohol modulates function of several

receptors and cell functions:

• GABAa receptors

• Kir3/GIRK channels

• return entry of adenosine

• glycine receptors

• NMDA receptors

• 5-HT3 receptors

Alcohol

• Physical addiction becomes evident

after 6-12 hours of heavy drinking

cessation.

• Abstinence syndrome: tremor (mostly

hand tremor), vomit, nausea, excessive

sweating, agitation and hearing

hallucinations 12 to 24 hours after

drinking cessation.

Alcohol

• Generalised convulsions can appear 24

to 48 hours after drinking cessation.

• After 48 to 72 hours delirium tremens

can appear: patient is disoriented,

hallucinates and there is autonomic

instability.

• Mortality rate of delirium tremens

is 5-15%.

Treatment

Treatment of alcoholabstinence syndrome is basedon lorazepam and oxazepam.

Psycho-social approach is veryimportant.

Ketamin and phencyclidine

Ketamin and phencyclidine are non competitive antagonists of NMDA receptors.

Psychedelic affect lasts for about an hour.

They do not cause addiction.

Chronic abuse can cause permanentpsychosis similar to schizophrenia.

Inhalant drugsNitrates, ketones and aromatic

hydrocarbons: sniffing, huffing or bagging.

Most of inhalant drugs create euphoria: for example, toluene

causes increase in VTA excitability.Amyl nitrate (poppers) cause

smooth muscle relaxation andimprove erection.

VTA: ventral tegmental area

Inhalant drugs

They have toxic affect on many organs.

They cause lesions of white matter in central nervous system.

Treatment of overdose is supportive.