The GABA receptor How does it work
And the last part here before we jump into these drugs is the structure and function of this GABA Chloride Ion Channel that we can see right here. So just taking a first look at it right, this is a GABA Chloride Ion Channel and the neurotransmitter is GABA. Now, I didn't mention this earlier because I didn't want to overwhelm you. but notice here, it's not just 1 GABA that needs to bind but actually 2 GABAs need to bind in order to let an ion through here. So I'm just going to write a neurotransmitter x 2. What is this receptor calledé
Well it's called the GABA A receptor and the reason it's called the GABA A receptor is due to the actual type of subunits that comes through that comprises this channel and also, the ion that goes through it. And we'll talk about GABA B on the next slide. What is the ion hereé Well, the ion is called Chloride. And so, what happensé Chloride comes into the cell and it makes the inside of the cell slightly more negative
and the effect of that is an inhibitory postsynaptic potential. So, let's put these all in context because it's kind of confusing unless you see it all together. So let's just say here is my presynaptic neuron and let's say here's my postsynaptic neuron. Now, I'm going to draw this a little different than you might see it because we're going to add something to it here in a second. So what's going on hereé
Well, we've got a different color. So we have an action potential right. It comes down the cell. We have this voltage gated calcium channel, this allows calcium to come in right. And so, calcium comes in and it causes the fusion of these vesicles and what are these vesicles containingé They're containing GABA. And so, from this presynaptic neuron, these vesicles traverse across the synaptic cleft and they will bind to a receptor on the postsynaptic membrane. So let's just say here is the ion channel, here is the receptor. That's what we're looking at right here.
That receptor is that one here. So here's step one, action potential comes. Two, calcium comes in. Three, we get the fusion GABA and four, it diffuses across. Five, it binds to the receptor and that's what we're seeing here. And so six would be the Chloride ions that are here coming into the postsynaptic neuron causing an inhibitory postsynaptic potential and so, that's what we see right here. Now, this isn't the only neuron that's interacting with this postsynaptic neuron righté We can also have an excitatory one that's synapsing here as well. So, I'm not going to draw everything like I did before but let's say we have all of these steps
but instead of GABA coming here, let's say we have (man! it's crazy how nice colors look) let's say we have glutamate. That was a silly comment. And so, with glutamate right it also binds to its own receptor but in this case, let's say, it lets sodium in and now, we have an excitatory postsynaptic potential. And so, what this cell is doing is it well it says, okay, is there more positive or is there more negativeé If there's more positive, is it enough to reach thresholdé And if there is, then maybe I'll list another action potential here and here are these you know sodium channels on the axon that allow charge to come through. Remember anywhere you block along this path, well you can mess things up.
Alzene 10mg Tablet powerpoint
pharmaceutical research by Kathy Wang drug overview Alzene tablet contain the active ingredient cetirizine hydrochloride it is a powerful immediate release medication that relieve allergic symptoms. today's objective is to discuss the biopharmaceutical considerations formulation and excipient function of Alzene 10mg tablet. biopharmaceutics
Alzene tablet is an antihistamine medication that is effective for symptom relief of the following allergic conditions Seasonal allergic rhinitis and Perennial allergic rhinitis Chronic idiopathic urticaria. the recommended duration of therapy is to stop taking the medication once symptoms have eased and restart if symptoms reappear. the antihistamine activity begins within one to three hours and last for atleast 24 hours after a single dose
the rapid onset of effect and once daily dosing is major advantage of this medication cetirizine hydrochloride is the active metabolites of hydroxyzine produced in body it is a potent antagonist that seletively antagonises the peripheral histamine receptor and inhibits histamine release with no affinity for H2 receptor. in addition citirizine also showed a decrease in eosinophil migration to the skin
during the late phase allergic reponse. compared to first generation antihistamine, cetirizine is less lipophilic due to the carboxyl group. as a result, it has a reduced penetration across the blood brain barrier and produces minimal sedation. pharmacokinetics absorption following oral administration Alzene tablet is rapidly absorbed reaching peak plasma concentration after 1 hour of dosing. its approximate
oral bioavalibility is greater than 70%. food has no impact on bioavalibility but can delay absorption rate by around one hour with lower peak plasma concentration by 23% this can be a pharmacokinetic barrierthe drug undergoes before getting to target site distribution. alzene tablet has high plasma protein binding of 93% and low apparent volume distribution. this indicate that the drug has high affinity for vascular system
rather than the lean tissues thus minimal effect on cardiotoxicity cetirizine has low CNS penetration and is a substrate of PGP which is also a barrier. metabolism alzene tablet has minimal hepatic first pass metaoblism and low degree of Odealkylation metabolism. therefore it has low potential to interact with liver CYP enzyme the biopharmaceutical barrier of first pass metabolism