PHARM - Introduction to Pharmacology of the Nervous System - Week 3 Flashcards
Describe Loewi’s experiment. What does it indicate.
The beating heart of an animal is removed, and kept beating. The vagus nerve can be stimulated could decrease the heart rate.
Leowi perfused one heart with saline solution, and hooked it up to a recipient heart. This resulted in both hearts slowing down and indicated there was a process of chemical transmission acting here.
Name 8 major pharmacological manipulation sites at a synapse.
-The action potential propagation (ion channels responsible for them)
-Neurotransmitter synthesis (blocking or stimulating involved pathways)
-Neurotransmitter storage (within vesicles which can be targetted)
-Metabolic processes involved with the neurotransmitter
-Vesicle fusion with the pre-synaptic terminal
-Neurotransmitter inactivation
–Uptake (can be metabolised or repackaged)
–Degradation
-Post-synaptic receptor
Define pre-junctional receptors.
Receptors found on the pre-synaptic cleft similar to those found on the post-synaptic membrane. They can act as negative feedback processes.
What are the two major chemical transmitters for the peripheral nervous system?
Noradrenaline
Acetylcholine
Name 4 receptor families activated by neurotransmitters.
Ligand-gated ion channels (ionotropic receptors)
G-protein-coupled receptors (metabotropic receptors)
Kinase-linked receptors
Nuclear receptors
Name 4 kinds of ion channels.
Voltage-gated
Ligand-gated
Membrane delimited metabotropic (directly acted on by g-protein)
Diffusible second-messenger metabotropic (g-protein activates a second messenger)
Describe a simple 3 neuron system.
Two nerve inputs into the cell body of a third neuron.
One of the two inputs has excitatory (glutamate/ACh) the other is inhibitory (GABA/glycine)
Whether the output nerve will fire depends on the relative strength of the inputs. Whichever reaches its threshold will determine the firing.
Explain what a 3 neuron system would look like realisticly.
Each nerve would have many inputs, each excitatory or inhibitory. The effect that upregulating or inhibiting one or more of these would therefore be very complex, and knowing what effect it would have as a whole is difficult.
What chemical mimicks the following systems:
Somatic
Parasympathetic
Sympathetic
Ganglionic transmission
Somatic - Ach
Parasympathetic - Ach
Sympathetic - Noradrenaline
Ganglion - Ach
Where are nicotinic receptors typically found (3)?
Between pre- and post-gangionic cells of the sympathetic and parasympathetic nervous system, as well as on skeletal muscles.
What receptors do the parasympathetic system use?
Muscarinic
What receptors do the sympathetic system use?
Adrenoreceptors a and B
What effect does the sympathetic system have on the following:
Heart rate
GIT
Pupils
Arteries
Glands
Bronchi
Heart rate - increase
GIT - decreased activity
Pupils - dilation
Arteries - constriction
Glands - none
Bronchi - dilation
What effect does the parasympathetic system have on the following:
Heart rate
GIT
Pupils
Arteries
Glands
Bronchi
Heart rate - decrease
GIT - increased activity
Pupils - constriction
Arteries - none
Glands - secretion
Bronchi - constriction
