biochem chemical communication Flashcards
a nerve cell
neuron
a molecule that blocks a natural receptor site
antagonist
a chemical messenger between a neuron and another target cell
neurotransmitter
a chemical messenger released by an endocrine gland into the blood stream
hormone
distinction between a neurotransmitter and a hormone is?
physiological, not chemical
a molecule that competes with a natural messenger for a receptor site; binds to the receptor site and elicits the same response as the natural messenger
agonist
a drug may increase depends on the
effective concentration of a messenger
messengers are also classified by how they work; they may:
-activate enzymes
-affect the synthesis of enzymes
- affect the permeability of the membranes
-act directly through a secondary messenger
five classes of chemical messengers
cholinergic
amino acid
adrenergic
peptidergic
steroid
the main cholinergic messenger
acetylcholine
two kinds of receptors for acetylcholine
muscarinic and nicotinic)
receptors on muscle neurons are called
nicotinic receptors
the message of ACh is initiated by
Ca+
when ____ concentration becomes more than ____the vesicles that contain ACh ____ with the ______ of the _____ and empty ACh into the ______
-Ca+
- 0.1
- fuse
- presynaptic membrane
- nerve cells
- synapse
ACh is removed form the receptor site by hydrolysis catalyzed by the enzyme _______
acetylcholinesterase
ACh is removed form the receptor site by
hydrolysis
this rapid removal allows nerves to transmit more than?
100 signals per second
acetylcholinesterase is inhibited irreversibly by the ______ in nerve gases and some ______
-phosphonates
- Pesticides (ChemCom 24b)
acetylcholine is inhibited by these two compounds;
succinylcholine, decamethonium bromide
ACh enables ______ to open and propagate signals, these channels are called____
-ion channels
-Ligand-gated ion channels
nicotine in low doses is a
stimulant
nicotine in high doses is an
antagonist
examples of excitatory neurotransmitter
Glu, Asp, Cys
2 EXAMPLES OF AMINO ACID MESSENGERS
excitatory neurotransmitter
inhibitory neurotransmitter
examples of inhibitory neurotransmitter
Gly, Taurine, Alanine, Aminobutyric acid(GABA)
glu has at least how many subclasses of receptors?
5
they reduce neurotransmission, examples are Gly,Taurine, Alanine, Aminobutyric acid(GABA)
inhibitory neurotransmitter
best known subclasses of receptor in Glu (amino acid)
N-methyl-D-aspartate (NMDA) receptor
what type of receptor is the NMDA
ligand ion gated channel
NMDA or Glu is closed by which ion?
Mg2+
4 monoamines, these monoamines transmit signals by mechanism whose beginning is similar to the action of acetylcholine
Epinephrine, dopamine, serotonin, histamine
-it activates G protein hydrolyzes GTP
-The energy of hydrolysis activates adenylate cyclase
norepinephrine
when norepinephrine is absorbed onto the receptor site;
-it activates G protein hydrolyzes GTP
-The energy of hydrolysis activates adenylate cyclase
is synthesized in cells from ATP
cAMP
3 cyclic AMP (cAMP)
-ADENOSINE TRIPHOSPHATE
-CYCLIC ADENOSINE MONOPHOSPHATE
-PYROPHOSPHATE
protein that blocks the channel ion flow
The catalytic unit phosphorylates the ion- translocating
the protein that changes it’s chape and position and opens the gate
phosphorylated ion-translocating protein
2 adrenergic neurotransmitters
epinephrine, norepinephrine
receptors that are found in the respiratory tract
H1
receptors that are found in the stomach
h2
the body inactivates monoamines by ______ to an aldehyde
oxidation
the body inactivates monoamines by oxidation to an aldehyde, catalyzed by ______
monoamine oxidases
the first brain peptides isolated were the _____
enkephalins
all peptidergic messengers, hormones and neurotransmitter act through
secondary messengers
are present in certain nerve cell terminals
pentapeptides
these uses membrane- derived phosphatidylinositol (PI) derivatives
vasopressin
vasopressin uses membrane-derived
phosphatidylinositol (PI) derivatives
these use the G-protein in a adenylate cyclase cascade
-Glucagon
-Luteinizing hormone, antidiuretic hormone, angiotensin, enkephalin, and substance P
large numbers of hormones are_____
steroids
steroid hormones are ____ therefore, cross the plasma membranes through diffusion
hydrophobic
steroid messengers are located in the
nucleus
once inside the nucleus, the steroid-receptor complex can either bind directly to DNA or combine with a transcription factor
