SINAPSIS

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SINAPSIS
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Qué libera la vesícula sináptica? Cómo recibe
al mensajero la neurona postsináptica?
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Dos clasesdereceptores para los NT A. Receptores
inotrópicos. Receptores que unen el NT y ellos
mismos sonun canal iónico. B. Receptores
metabotrópicos. Receptores que unen el NT y
através de ProteinasG (proteinas que unen GTP)
regulan actividad de canales ionicos
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Receptores inotrópicos. Receptor nicotínico de
ACh-Son diferentes de los canales
voltaje-dependientesdel Na y del K canal grande
que permite el paso de ambos Na y Ka favor de
gradiente.
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• Neurotransmision mediada por segundos
  mensajeros-Diseño
• ligando-receptor transductor (proteinaG)
  -efector primario (adenilciclasa) mensajero
  secundario (AMPc) -efector secundario-
  proteinkisana-respuesta celular

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• Efectode lafosforilaciónde proteinas
• A. Proteinkinasa fosforila las proteinas de un
  canal de K-apertura canal paso de K propagación
  del potencial sináptico (respuestaenminutos)
• B. Proteinkinasa fosforila proteinas de
  transcripcion (reguladoras) regulación de
  expresión genica (reprimiendo y/o expresando
  genes). Respuesta tardía y sostenida en el
  tiempo.

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Neurotransmisores derivados de aminoácidos y
neuropéptidos. Receptores Neurotransmisión y
neuromodulación

• 1. Sinápsisquímica implica
• a.síntesis del neurotransmisor
• b.liberacióndelneurotransmisor
• c.interacción NT-receptor
• d.remoción del NT.
• 2.Conceptode NT
• Sustancia liberada en la sinapsis por una neurona
  y que afecta a otra célula de una manera
  especifica. Principio de Dale-Ecclesactualizadoun
  a neurona hace uso de la misma combinaciónde
  mensajeros quimicos entodas sus terminaciones
  sinapticas.
• El sistema nervioso utiliza dos clases de
  mensajeros químicos
• a. moléculas pequeñas
• b. neuropéptidos.

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• Schematic representation of the life cycle of a
  classical neurotransmitter. After accumulation of
  a precursor amino acid into the neuron (1), the
  amino acid precursor is metabolized sequentially
  (2) to yield the mature transmitter. The
  transmitter is then accumulated into vesicles by
  the vesicular transporter (3), where it is poised
  for release and protected from degradation. Once
  released, the transmitter can interact with
  postsynaptic receptors (4) orautoreceptors(5)
  that regulate transmitter release, synthesis, or
  firing rate. Transmitter actions are terminated
  by means of a high-affinity membrane transporter
  (6) that is usually associated with the neuron
  that released the transmitter. Alternatively,tranm
  itteractions may be terminated by diffusion from
  the active sites (7) or accumulation into glia
  through a membrane transporter (8). When the
  transmitter is taken up by the neuron, it is
  subject to metabolic inactivation (9).

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Sinapsis Noradrenergica
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Sinapsis noradrenergica

• Characteristics of a norepinephrine
  (NE)-containing catecholamineneuron. Tyrosine
  (Tyr) is accumulated by the neuron and is then
  metabolized sequentially by tyrosine hydroxylase
  (TH) and L-aromatic aminoacid decarboxylase
  (L-AADC) to dopamine (DA). The DA is then taken
  up through the vesicular monoamine transporter
  into vesicles. In DA neurons, this is the final
  step. However, in this NE-containing cell, DA is
  metabolized to NE by dopamine-b-hydroxylase
  (DBH), which is found in the vesicle. Once NE is
  released, it can interact with postsynaptic
  noradrenergic receptors or presynaptic
  noradrenergic autoreceptors. The accumulation of
  NE by the high-affinity membrane NE transporter
  (NET) terminates the actions of NE. Once taken
  back up by the neuron, NE can be metabolized to
  inactive compounds (DHPG) by degradative enzymes
  such as monoamineoxidase (MAO) or taken back up
  by the vesicle.

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Sinapsis Seroninergica
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Sinapsis serotoninergica

• Aminas derivada de triptofamo (indolaminas-Seroto
  nina(SER), melatonina-Serotonina
• triptófanotriptofano hidroxilasa--gt 5-Hidroxi
  triptofano5-Hidroxi triptofano
  decarboxilasa--gt 5-HT (SER) Serotonergic neuron.
  Tryptophan(Trp) in the neuron is metabolized
  sequentially bytryptophan hydroxylase (TrypOHase)
  and L-AADC to yield serotonin (5-HT). 5-HT is
  accumulated by the vesicular monoamine
  transporter. When released, 5-HT can interact
  with both postsynaptic receptors andpresynaptic
  autoreceptors. 5-HT is taken up by the
  high-affinity 5-HT transporter (SERT), and once
  inside the neuron it can be reaccumulated by
  vesicular transporter or inactivated metabolica

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Acetilocolina
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Production of acetylcholine
(choline acetyltransferase)
(acetylcholinesterase)
Breakdown of acetylcholine
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Sinapsis colinergica

• Acetylcholine (ACh) synthesis, release, and
  termination of action are shown.
  Acholinetransporter accumulatescholine. The
  enzymecholine acetyltransferase(ChAT) acetylates
  thecholineusing acetyl-CoA(Ac-CoA) to form the
  transmitterACh, which is accumulated into
  vesicles by the vesicular transporter. The
  releasedAChmay interact with postsynapticmuscarini
  cor nicotiniccholinergicreceptors or can be taken
  up into the neuron by acholinetransporter.
  Acetylcholine can be degraded after release by
  the enzyme acetylcholine esterase (AChE).

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Sinapsis Gabaérgica
Alpha-Ketoglutarate
GABA-oxoglutarate transaminase (GABA-T)
Glutamate
Glutamic acid decarboxylase (GAD)
GABA
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F I N