Gaba a - increased cl- conductance-2. beta-1 adrenergic - increased camp-3. 5-ht3 - increased cation conductance-answer: cfg
(katzung, pp 345, golan pp 82)
all gaba receptors are inhibitory. therefore they must hyperpolarize the postsynaptic
membrane. gaba a receptors do so by increasing cl- conductance whereas gaba b receptors
do the same by increasing k+ conductance. all beta receptors are metabotropic and act by
increasing the synthesis of the second messenger camp. 5-ht3 receptors are mainly
excitatory. therefore they must depolarize the postsynaptic membrane. by increasing cation
conductance na+ can enter the cell and depolarization occurs.
a) m3 receptors are mainly excitatory. a decrease in na+ conductance would cause an
inhibitory effect at the postsynaptic membrane. actually activation of these receptors causes
the increased synthesis of ip3/dag
b) alpha-1 adrenergic receptors are excitatory. a decrease in ca++ conductance would cause
an inhibitory effect at the postsynaptic membrane. actually activation of these receptors
causes the increased synthesis of ip3/dag
d) glycine receptors are inhibitory and cause hyperpolarization of the postsynaptic membrane
by increasing, not decreasing, cl- conductance.
e) nmda receptors are glutamate receptors. all glutamate receptors are excitatory and cause
depolarization of the membrane by increasing, nor decreasing, cation conductance.