Mcqs In Histochemistry Of Biogenic Amines

Prof.Dr. Ashour Abdelsalam Tumor Cell Biology Dept. Medical Research Institute

Date: 10/01/2009

Ph.D. Examination Non-enzyme histochemistry (Biogenic amines) A) Choose the right answer (s): 1. The first identified neurotransmitter, acetylcholine a. is an amino acid derivative b. acts at neurotransmitter junction c. has a characteristic enzyme in its biosynthesize d. all of the above Correct: b & c 2. Amine-handling cells are those that a. synthesize, store and secret biogenic amines b. synthesize but don't store biogenic amines c. secret but don't synthesize biogenic amines d. secret and store biogenic amines Correct: a 3. VMAT2 is the exclusive vesicular monoamine transporter found in a. serotoninergic neurons b. adrenergic and noradrenergic neurons c. dopaminergic neurons d. tyraminergic neurons Correct: a, b & c 4. The catecholamine neurotransmitters include a. histamine b. serotonin c. acetylcholine d. non of the above Correct: d 5. Trace biogenic amines include a. octopamine b. phenylethylamine c. tyramine d. tryptamine e. all of the above Correct: e 6. The catecholamines are synthesized from the amino acid a. tryptophan b. tryptamine c. tyrosine d. tyramine Correct: c 7. The rate limiting enzyme that catalyze all catecholamine biosyntheses is a. phenylalanine decarboxylase b. dopamine hydroxylase c. tyrosine hydroxylase d. pteridine reductase Correct: c

8. The enzyme that converts L-dopa to dopamine is a. aromatic acid decarboxylase b. dopamine-b-hydroxylase c. phenylalanine decarboxylase d. pteridine reductase Correct: a 9. Noradrenalin is synthesized from dopamine through the enzyme a. a. aromatic acid decarboxylase b. dopamine-b-hydroxylase c. phenylalanine decarboxylase d. pteridine reductase Correct: b 10. The only enzyme in neurotransmitter biosynthesis pathways that is a membrane-associated enzyme is a. aromatic acid decarboxylase b. dopamine-b-hydroxylase c. phenylalanine decarboxylase d. pteridine reductase Correct: b 11. Dopamine neurotransmitter a. is not related to catecholamine b. involves in coordination of body movement c. increase cardiac output d. is synthesized from adrenalin Correct: b & c 12. Noradrenalin is a biogenic amine that involves in a. sleep b. attention c. wakefulness d. body movement Correct: a, b & c 13. Adrenalin is a biogenic amine that: (a) is a stress hormone synthesized from noradrenalin and (b) plays a role as a neurotransmitter a. (a) & (b) are correct c. (b) is only correct b. (a) is only correct d. (a) & (b) are not correct Correct: a 14. The major enzyme that involves in catecholamine catabolism is (a) monoamine oxidase (b) catechol O-methyltransferase a. (a) & (b) are correct c. (a) is only correct b. (a) & (b) are not correct d. (b) is only correct 15. Histamine a. is derived from tyrosine amino acid b. is synthesized from histidine amino acid c. its precursor catalyzing enzyme is monoamine oxidase d. is synthesized through both enzymes histidin methyltransferase and monoamine oxidase Correct: b & d

16. Histamine is released from mast cells in response to (a) allergic reactions (b) in response to tissue damage a. (a) is only correct b. (b) is only correct c. (a) & (b) are correct d. (a) & (b) are not correct Correct: c 17. Serotonin is a central nervous system neurotransmitter involves in regulating a. mood b. sleep c. sexuality d. body movement Correct: a, b & c 18. 19.

Cross match 1. Acetylcholine Serotonin 2. Acetylcholine synthesis Histamine synthesis 3. VMAT1 VMAT2

4. VMAT1 VMAT2 5. Dopamine Serotonin 6. Cholinergic neurons Epinephrinergic neurons 7. Amine-handling cells Catecholamine transmitters

is related to catecholamine moiety is the first identified neurotransmitter has an indol ring is catalyzed by monoamine oxidase is catalyzed by histidin decarboxylase is catalyzed by cholin acetyltransferase is a neuronal transporter is an endocrine transporter is a general histochemical marker for biogenic amines is a biogenic amine marker in gut is the endocrine vesicular amine transporter recognizes as transport substrates trace biogenic amines has a catecholamine moiety has an indol moiety is not an amino acid derivative are acetylcholine containing neurons are tyramine containing neurons are adrenalin containing neurons are dopamine, adrenalin and noradrenalin are chromaffine cells synthesize, store and secret biogenic amines

Fill in the spaces 1. Biogenic amines containing neurons are grouped into dopaminergic, adrenergic, noradrenergic, serotoninergic and histaminergic. 2. To store amines in secretory organelles, amine-handling cells express vesicular amine transporters like VMAT1, VMAT2 and VACHT. 3. VMAT1 is an endocrine transporter while VMAT2 is a neuronal transporter. 4. VMATs provide an insight into the mechanisms of line age determination because they are expressed in developing as well as mature neurons. 5. Histamine is refered as a biogenic amine although it is neither catecholamine nor indolamine. 6. The first step in catecholamine synthesis is catalyzed by tyrosine hydroxylase. 7. L-dopa is synthesized from tyrosine. 8. Noradrenalin is the only biogenic amine that is synthesized within vesicles. 9. Although dopamine does not cross blood brain barrier, its precursor L-dopa dose. 10. Dopamine is transported by vesicles into adrenergic terminals where it is converted to noradrenalin. 11. Monoamine oxidase is a catalyzing enzyme for catecholamines. 12. Histidine is the precursor of histamine. 13. Two enzymes are needed to synthesize serotonin: tryptophan hydroxylase and 5-hydroxytryptophane decaroboxylase. 14. Endogenous amines are produced in many different tissues while the exogenous amines are directly absorbed from food in the intestine. 15. Trace amines are endogenous compounds structurally related to classical biogenic amines.

Short notes Write in brief about: 1. Vesicular monoamine transporters 2. Catecholamines 3. Synthesis of histamine 4. Biogenic amines derived from amino acids 5. A stress hormone 6. Amine-handling cells 7. Histochemical identification of two different biogenic amines 8. Trace biogenic amines 9. Exogenous and endogenous biogenic amines