Term
| Describe electrical field stimulation |
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Definition
| Tissues were placed under a resting of 0.5g and attached to an isometric transducer that converts changes in tension to an electrical impulse that can be recorded on the PC screen. The electrode is connected to a stimulator which you will use to fire trains of pulses to the tissue. |
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Term
| Describe bath stimulation |
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Definition
| Drug concentration is added to the bath and contractions are measured. The tissue is washed before other concentrations/repeats are done. |
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Term
| What receptors are found in vas deferens? |
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Definition
Postsynaptic α1 adrenoceptors
Presynaptic α2 adrenoceptors |
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Term
| What receptors are found in illeal smooth muscle? |
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Definition
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Term
| What receptors are found in tracheal smooth muscle? |
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Definition
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Term
| What receptors are found in aortic smooth muscle? |
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Definition
Postsynaptic α1 adrenoceptors
Presynaptic α2 adrenoceptors |
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Term
| What receptors are found in cardiac/ventricular muscle? |
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Definition
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Term
| Describe the β adrenergic pathway |
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Definition
1. Gs
2. activates adenylyl cyclase
3. ATP is converted into cAMP
4. increase PKA |
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Term
| Describe the α2 adrenergic pathway |
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Definition
1. Gi
2. inhibits adenylyl cyclase
3. ATP is not converted into cAMP
4. less PKA |
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Term
| Describe the α1 adrenergic pathway |
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Definition
1. Gq
2. Phospholipase C
3. PIP2 is cleaved into IP3 and DAG
4a. IP3 increases intracellular Ca2+
4b. DAG increases PKC |
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Term
| Name some agonist and antagonists for cardiac/ventricular muscle |
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Definition
Agonists: NA, adrenaline, isoprenaline.
Antagonists: propranolol |
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Term
| Name some agonist and antagonists for tracheal smooth muscle |
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Definition
Agonists: NA, adrenaline, isoprenaline.
Antagonists: propranolol |
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Term
| Name some agonist and antagonists for vas deferens smooth muscle |
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Definition
Agonists: NA, adrenaline,
α1 phenylepherine; α2 clonidine
Antagonists: α1prazosin; α2 yohimbine |
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Term
| Name some agonist and antagonists for aortic smooth muscle |
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Definition
Agonists: NA, adrenaline, α1 phenylepherine; α2 clonidine
Antagonists: α1 prazosin; α2 yohimbine |
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Term
| Name some agonist and antagonists for ileal smooth muscle |
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Definition
Agonists: carbachol.
Antagonists: Atropine |
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Term
| What do sympathetic preganglionic neurones release? |
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Definition
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Term
| What do sympathetic postganglionic neurones release? |
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Definition
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Term
| Describe the events that occur at a neuromuscular junction |
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Definition
1. ca2+ enters the presynaptic terminal and causes the release of ACh into the synaptic cleft
2. Ash binds to nicotinic acetylcholine receptor
3. sodium enters the postsynaptic terminal
4. ACh is broken down into choline and acetate via acetylcholine esterase |
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Term
| Describe the events that occur at noradrenergic varicosity |
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Definition
1. AP arrives
2. ATP and noradrenaline are released into the synaptic cleft
3. noradrenaline binds to auto receptors and causes a decrease in cAMP
4. reduced cAMP decreases Ca2+ entering
5. Ca2+ entering increasing ATP and noradrenaline release (negative feedback control) |
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Term
| What happens when noradrenaline binds to an a1receptor? |
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Definition
increased IP3
increased ca2+ release from endoplasmic reticulum
increased contraction |
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Term
| What happens when ATP binds to an a2receptor? |
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Definition
| aids the entry of ca2+ to increase contraction |
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Term
| How does clonidine affect the contraction of vas deferens? |
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Definition
- clonidine is a alpha-2 agonist and binds to presynaptic receptors to reduce cAMP levels and reduce presynaptic Ca2+ intake
- Less ca2+ is available to induce ATP and NE release, therefore less binds to the post-synaptic membrane
- Less Ca2+ enters post synaptic membrane and there is less a1 stimulation therefore less contraction |
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Term
| How does yohimbine affect the contraction of vas deferens? |
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Definition
- yohimbine is an alpha 2 antagonist and decreases cAMP levels which would otherwise have an inhibiting effect on ca2+ levels
- ca2+ induces ATP and NE release
- ATP induces ca2+ entry on the post-synaptic membrane and NE binds to a1 receptors on the smooth muscle
- both lead to contraction |
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Term
| Which agonists would elicit a response for aortic smooth muscle? |
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Definition
| phenylephrine and isoprenaline |
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Term
| Which agonists would elicit a response for tracheal smooth muscle? |
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Definition
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Term
| Which agonists would elicit a response for cardiac smooth muscle? |
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Definition
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Term
| Which agonists would elicit a response for illeal smooth muscle? |
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Definition
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Term
| What G proteins are associated with the muscarinic receptors? |
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Definition
M1 - Gq
M2 - Gi
M3 - Gq
M4 - Gi
M5 - Gq |
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Term
| What G proteins are associated with the adrenoreceptors? |
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Definition
alpha 1 - Gq
alpha 2 - Gi
beta - Gs |
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