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Cell Signaling1. Synthesis, release, transport of signaling molecules
- neurotransmitters, hormones, etc- ligand binds to a specific receptor
2. Reception of information by target cells
3. Signal transduction- receptor converts extracellular signal into
intracellular signal- causes change in the cell
4. Response by the cell
Fig. 6-3, p. 137
Cell Signaling
Receptors
Figure 12.2b
Functional Overview of the Nervous System
Figure 13–14
5 Steps in a Neural Reflex
Nerve Structure
Neuron Structure
Electrochemical Gradients
Figure 12.12
Figure 12.11
An Introduction to the Resting Potential
Electric eel600 volts
Figure 12.13
*Canalopatías“channelopathies”
The first demonstration that channelopathies could affect nerves as well as muscles came in 1995, when researchers discovered that episodic ataxia type 1, a rare autosomal dominant disease, results from mutations in one of the potassium channel genes.
Paramyotonia congenita is due to mutations in the gene coding for the α1 subunit of the sodium channel,
Thomsen’s disease (autosomal dominant myotonia congenita) and Becker’s disease (autosomal recessive myotonia congenita) are allelic disorders associated with mutations in a gene coding for skeletal muscle chloride channel.
Familial hyperkalaemic periodic paralysis is due to mutations in the same sodium channel gene as that affected in paramyotonia congenita, while
Familial hypokalaemic periodic paralysis results from mutations in the gene coding for the α1 subunit of a skeletal muscle calcium channel.
Synaptic Transmission
Electrical synapses
Chemical synapses
Fig. 6-5, p. 139
Receptores:
Ionotróficos Metabotróficos
Neuropeptidos (encefalinas y endorfinas), endocannabinoides
(Glutamato)
(Tyrosina)
(Histidina) (Triptófano)
Fig. 40-10b, p. 858
Axon of presynaptic neuron
Synaptic terminal
Voltage-gated Ca2+ channel 1
Ca2+Synaptic vesicle2
Neuro- transmitter molecule
3
4
Ligand-gated channels
Postsynaptic membrane
5
Postsynaptic neuron
Receptor for neurotransmitter
How a neural impulse is transmitted across a synapse.
Ion Channel–Linked Receptor
Voltage-Activated Ion Channels
Tetradotoxina (pez globo), Saxitoxina (dinoflagelado marea roja) y cocaína –bloquean canales sodio voltajeCiguatoxina– facilitan canales sodio voltaje
Zombis– Tetradotoxina (bloquean canales sodio) + Datura (campana) –anticolinérgico.
*Canalopatías“channelopathies”
Figure 12.2b
Anatomy of a Multipolar Neuron
Figure 12.15
Depolarization and Hyperpolarization
EPSP – IPSP Interactions
Figure 12.23
Voltage-Activated Ion ChannelsDuring an Action Potential
Transmission of an Action
Potential
No-myelinadasTypeC 2mph
MyelinadasTypeB 40mphTypeC 268mph
Fig. 40-10b, p. 858
Axon of presynaptic neuron
Synaptic terminal
Voltage-gated Ca2+ channel 1
Ca2+Synaptic vesicle2
Neuro- transmitter molecule
3
4
Ligand-gated channels
Postsynaptic membrane
5
Postsynaptic neuron
Receptor for neurotransmitter
(b) How a neural impulse is transmitted across a synapse.
GABA y Serotonina
Receptor nicotínico Acetilcolina
Bungarotoxina (de la serpiente krait) antagonista receptor nicotínico AcetilcolinaParálisis y fallo respiratorio
Myasthenia gravis
Botulinum toxin Clostridium botulinum
Tetanus toxin & Strychnine
Fig. 6-3, p. 137
Fig. 6-5, p. 139
Receptores:
Ionotróficos Metabotróficos
Fig. 6-5, p. 139
G Protein–Linked Receptors
Fig. 43-13a, p. 933
1
2
5
34
Parasympathetic neuron
Acetylcholine
Acetylcholine receptor K + channel K +
Plasma membrane
G-protein
K +
Cardiac muscle
Receptor muscarínicopara acetilcolina
Fig. 43-13b, p. 933
Sympathetic neuron
1
Norepinephrine
-adrenergic receptor
Gate open
G protein Plasma membrane
2 6 Ca2+
Adenylyl cyclase
4ATP Ca2+
3
cAMP 5Cardiac muscle
Protein Kinase
Second Messenger
Signal Amplificationand SignalIntegration
Receptor Affinity-dissociation constant
Receptor Down Regulation-receptor mediated endocytosis-desenzitation
Drugs as agonist and antagonists
Isoprotenerol (asthma) / propanolol hypertension) (B-adrenergic receptor)
Famotidine (Pepcid AC) / Cimetidine (Tagamet)(histamine receptor)
cAMPAumenta fuerza contracción corazónRelajación músculos lisosSecresión de NaCl en epitelio intestinal
Inhibidores de fosfodiesterasa:cafeína y teofilina
Proteína Gs y Gi
Toxina del cólera (Gs)Inhiben hidrólisis de GTP
Toxina pertussis (Gi) (Tos ferina)Inhiben sustituir GTP por GDP
G Protein and cAMP
Fig. 43-13b, p. 933
Sympathetic neuron
1
Norepinephrine
-adrenergic receptor
Gate open
G protein Plasma membrane
2 6 Ca2+
Adenylyl cyclase
4ATP Ca2+
3
cAMP 5Cardiac muscle
Protein Kinase
Fig. 43-13a, p. 933
1
2
5
34
Parasympathetic neuron
Acetylcholine
Acetylcholine receptor K + channel K +
Plasma membrane
G-protein
K +
Cardiac muscle
Receptor muscarínicopara acetilcolina
Esteres de forbolMimetizan DAG
Second Messengers
Calcium Regulation
Sildenafil inhibeFosfodiesterasa de cGMP
Long-Term Potentiation (LTP)
Enzyme-Linked Receptors
EGF- cancer de seno, glioblastoma y fibrosarcoma
TGFβ- 30% cancer de ovario y cancer colorectal
Smad4- 50% cancer de páncreas
Smad4- 50% cancer de páncreas
The tumor suppressor gene Smad4 (DPC4) at chromosome 18q21.1 belongs to the Smad family, which mediates the TGFb signaling pathway suppressing epithelial cell growth.