Scopolamine, atropine

These are muscarinic receptor antagonists.

Oxotremorine, arecoline, muscarine

These are muscarinic receptor agonists. They produce ataxia symptoms when activated (due to binding to the acetylcholine receptor.)

Physostigmine

An acetylcholinesterase inhibitor; it works by preventing the break down of AcH. AcH is implicated in memory consolidation, making this an effective treatment for Alzheimer's patients in the early stages.

Haloperidol, Clozapine, Chlorpromazine

These are antipsychotics. They are D2 receptor antagonists.

Amphetamines

Methamphetamine is a common drug, and one of the most neurotoxic. It has a double-effect; it prevents reuptake of DA and is also a VMAT and COMT inhibitor. This prevents it from leaving the synapse. Since it isn't catabolized, DA is oxidized, producing free radicals that kill neuronal cells.

Bromocriptine

Bromocriptine is a D2-receptor activator used to treat PD.

How does a D2-receptor (an autoreceptor) agonist INCREASE DA levels? Well it doesn't, it DECREASES dopamine! But the dopamine it effects is part of a system that DEACTIVATES motor movement, so you are essentially "disabling the STOP" pathway.

Apomorphine

More to come on Apomorphine. It is a D1 and D2-receptor agonist. Unfortunately it has strong emetic properties (as there are D2 receptors in the area postrema of the medulla that modulate this effect). Has been used to treat Parkinson's. Continued use is ineffective because of receptor desensitization.

Tolcapone

Tolcapone is a COMT inhibitor. It is extremely hepatoxic and is a last-resort drug. It inhibits COMT (the enzyme involved in the catabolism of dopamine and norepinephrine, the cathecholamines). It is often used to treat Parksinson's, as it prevents the breakdown of whatever dopamine might be left going to the striatum.

Atomoxetine

Atomoxetine (brand name Strattera) is a selective NE reuptake inhibitor (NET blocker), and is thus a treatment for ADHD.

Methylphenidate

Methylphenidate, commonly referred to by its label name of Ritalin, is used to treat ADHD. It has affinity for both DAT and NET proteins. By blocking reuptake, these NTs can act longer in the synapse.

Propranolol

Propranolol is a Beta-noradregenic receptor antagonist (beta blocker) with a wide variety of uses. It is used to treat hypertension.

It has been administered in the ER after a patient has undergone a traumatic event in order to blunt memories of the event (implicating NE in the role of memory consolidation). The effects of beta-blockers in blunting memory formation has not been conclusively validated, though it is a common practice.

Isoproteronol

Isoproteronol is a Beta-NE receptor agonist. It is used primarily for bradycardia or heartblock.

Yohimbine

Yohimbine is an alkaloid with stimulant and aphrodisiac properties. It is an alpha-2 antagonist. How does it achieve its effects as an antagonist? It primarily binds to the alpha-2-NE receptors that function as autoreceptors. Therefore, NE cannot bind to the autoreceptor, and so NE production and release in increased, resulting in the stimulant and aphrodisiac effects observed.

Clonidine

Clonidine is an alpha-2 NE receptor agonist. Alpha-2 NE receptors are Gi coupled (and therefore serve as autoreceptors).

Clonidine will preferentially bind to the alpha-2 NE receptors which are autoreceptors. Therefore, Clonidine, though an agonist, will actually decrease NE release, and has an almost identical effect to antagonists.

Prazosin

Keep in mind that norepinephrine normally has a vasoconstrictive effect. Prazosin is an alpha-1 NE receptor antagonist. The effects of NE are blunted, and blood vessels are relaxed, decreasing blood pressure.

Ephedrine, Phenylephrine, Pseudoephrine

These chemicals are alpha-1 Norepinephrine receptor agonists. Alpha-1 Norepinephrine receptors are Gq mediated. That is, they call upon the Phospholipase-C pathway, leading to IP3 and DAG. Calcium release is produced, as well as the phosphorylating effects of PKC.

Ephedrine-class compounds are used to treat the effects of hypotension. It is also an appetite supressant (consider Fen-Phen).

Venlafaxine

This is a newer, dual-mode antidepressant drug. It has been termed an SNRI, a serotonin-norepinephrine reuptake inhibitor.

Clorgyline

Clorgyline is an irreversible and selective inhibitor of monoamine oxidase A. Clorgyline prevents the breakdown of monamines, making it a potent antidepressant.

Tranylcypromine

Tranylcypromine is of the amphetamine chemical class. Amphetamines are Monoamine Oxidase inhibitors (MAO). MAO breaks down monamines (norepinephrine, dopamine, and serotonin) after they are taken up by the presynaptic cell. A MAOI prevents this breakdown, so that antidepressant effects are observed.

Desipramine

Desipramine is a tricyclic antidepressant (TCA). It prevents the reuptake of norepinephrine. Can be used to treat depression, ADHD, or neuropathic pain.

Alpha-Methyl-Para Tyrosine

Alpha-Methyl-Para Tyrosine (Alpha-Methyla-p Tyrosine, AMPT) is an inhibitor of Tyrosine Hydroxylase, the first enzyme involved in the serial production of norepinephrine. It was classically used as treatment for hypertension, but had Parkinson-like side-effects. It was really the only option for hypertension until new drugs were researched and developed.

Side-effects of AMPT administration is depressive mood, especially in patients who were on antidepressants. This is because the production of both NE and DA is inhibited.

Sildenafil

Sildenafil (commonly known as Viagra), is a phosphodiesterase inhibitor. Nitrious oxide is an unconventional neurotransmitter that can lead to cGMP production and thus the activation of certain kinases that result in vasodilation. Phosphodiesterases break down cGMP, so by inhibiting the breakdown of cGMP, a vasodilation effect can persist.

Rolipram

Rolipram is a phosphodiesterase inhibitor. Specifically, it is a PDE-4 inhibitor, and is thus an anti-inflammatory. It has potential therapeutic effects for a wide array of diseases and requires further research.

Black Widow Poison

Black Widow Poison is a SNARE protein activator, causing the constant binding of vesicles to the membrane. This will eventually lead to a dearth of neurotransmitter, paralysis, and eventually death. Note that it has the same effect as BoTox, but through an opposite mode of action.

BoTox

Botulinum toxin is a neurotoxic protein produced by a bacterium. It is a SNARE protein inhibitor. The SNARE proteins are responsible for docking vesicles to the membrane of presynaptic cells for exocytosis and release. BoTox prevents acetylcholine from being released, and thus causes paralysis. In the face, this prevents wrinkle formation (and hence gives BoTox its cosmetic properties).

Digoxin

Digoxin is an extract from a foxglove plant. It is a sodium-potassium ATPase pump inhibitor, used to treat a variety of heart conditions.

Ouabain

Ouabain, found in the ripe seeds of the plant Strophanthus gratus. It is a sodium-potassium ATPase pump inhibitor, preventing formation of the normal resting potential of neuronal cells. It has its etymological roots in Somali for "arrow-poison," as it has served as a useful weapon during war.

Agatoxin

This is a toxin primarily derived from spiders. Agatoxin binds to N and P-Ca++ channels, preventing neurotransmitter release by disrupting vesicle formation and release.

Conotoxin

Conotoxin is a toxin isolated from the venom of a sea snail. It blocks N and P-Ca++ Channels, preventing the transmission of neurotransmitter through vesicle formation and release.

Ethosuximide

Ethosuximide is a P-Ca++ channel blocker, used to treat petit mal seizure. Petit mal seizures are also called "absence seizures." This a period of seconds during which a person is "staring off into space" without any twitching or movement of the face of eye muscles.

Nifedipine

Nifedipine is a L-Ca++ channel blocker, used as an antianginal agent.

Verapamil

This drug is an L-Ca++ channel blocker and is used as a treatment for hypertension-related disorders.

Phenytoin

Phenytoin acts to suppress the abnormal brain activity seen in seizure by reducing electrical conductance among brain cells by stabilizing the inactive state of voltage gated sodium channels. It can be used to treat cardiac arrhythmias or trigeminal neuralgia. Trigeminal neuralgia is pathology of the trigeminal cranial nerve, which results in extreme, excruciating protopathic pain through very minimal stimulation of the side of a person's face

Carbamazepine

Carbamazepine (CBZ) is an anticonvulsant and mood-stabilizing drug. It's primary mode of action is stabilization of the inactive conformation of the Na+ channel of cell membranes. This reduces cell excitability, thus making it a potent treatment for those suffering from epilepsy or a manic stage in bipolar disorder.

Cocaine

Cocaine is one hell of a drug - scientifically. A potent stimulant, cocaine is a drug with widespread cultivation and use.

Perhaps I will devote more time to exploring the mechanisms of cocaine, suffice to say that it principally blocks dopamine reuptake into the presynaptic neuron. But for now, I will focus on on the following property of cocaine:

It is a local anesthetic, that has its effect by blocking Sodium channels. Ever wonder why DEA agents or police offers put a bit of white powder on their tongues to test if it is really cocaine? Not because of any distinct taste, but because it immediately numbs the tongue!

Tetrodotoxin

Tetrodotoxin is not a drug, but rather, a potent neurotoxin. Informally referred to as "tetrodox" it is often abbreviated TTX. Tetrodotoxin blocks action potentials in neuronal cells by binding to sodium (Na+) channels found in the membrane. This toxin is the product of certain bacteria, and found in pufferfish, porcupinefish, and oceanfish (There is a popular Simpsons episode that revolves around Homer lamenting his impending death after consuming Sushi that was laced with a certain toxin, which may be tangentially related to TTX).

The flux of Na+ and K+ is necessary for action potential propagation. Ingestion of the poison leads to paralysis (of the muscle - the cardiac muscle contains only "slow sodium channels,"). Death usually is a result of respiratory failure.

There is some interesting speculation that TTX is implicated in modern-day zombieism. A famous ethnologist suggested that Haitian voodoo practioners took TTX at near-lethal doses to create people who were "conscious" of their own death.

Welcome to My Blog

As an undergraduate Psychobiology major who hopes to study medicine, I've been immersed in a of topics dealing with the brain and psychopharmacological intervention used to treat a wide array of ailments. I am using this blog a sort of "notes journal." I will dedicate an entry to each drug I encounter in my studies, report the information and mechanisms I learn, and relate what the most current and up-to-date backed research states.