María Dolores Mayas-Torres⁽¹⁾, José Manuel Martínez-Martos⁽²⁾, María Jesús Ramírez-Expósito⁽³⁾, María Jesús García-López⁽⁴⁾, Isabel Prieto-Gómez⁽⁵⁾, Garbiñe Arechaga-Maza⁽⁶⁾, Manuel Ramírez-Sánchez^{(7)
(1)(2)(4)(5)(6)(7)}Unit of Physiology. University of Jaén - Jaén. Spain
⁽³⁾Unit of Physiology. University of Jaen - Jaén. Spain

	[Neuroscience]	[Physiology]

INTRODUCTION

Ethanol is the most psychoactive substance used after caffeine. Chronic alcohol intake is associated with several degenerative and inflamatory processes in the central nervous system (CNS) ^(1,2,3,4), and can induce a depressor effect in several inhibitory nervous centres ⁽⁵⁾. Due to the interest of alcohol dependence, several reports studies the ethanol capacity for increasing the membrane fluidity and changing the function of proteins that are inserted into the membrane ^(2,6,7). Other reports study the neurochemical pathways and the neurotransmitters that are implicated in this dependence ^(2,3,4). Therefore, it is not well known how the alcohol acts on the CNS.

The dependence to ethanol is characterized by a behavioural standard of chronic and compulsive intake of ethanol without the ability of having control of the use of this drug ^(8,9). Appart from the genetic causes, this behaviour seem to have particularly neurochemical causes ^(8,9).

Aminopeptidases (AP) are enzymes that hydrolize the peptide bonds near to the N-terminal amino acid of peptides and polypeptides. AP constituyes one of the principal pathways for neuropeptides inactivation and active peptides generation, through the hydrolysis of their precursors ⁽¹⁰⁾. Alanine aminopeptidase (AlaAP), leucine aminopeptidase (LeuAP) and tyrosine aminopeptidase (TyrAP, Enkephalinase) can hydrolyze different neuropeptides such as bradicinin ^(11,12), enkephalin ^(13,14) and may have angiotensinase activity ⁽¹⁵⁾. Arginine aminopeptidase (ArgAP) hydrolyzes particularly basic residues N-terminal from peptides and arylamide derivatives ⁽¹⁰⁾. Thanks to its exopeptidase activity, it has been implicated in the metabolism of Met-enkephalin ⁽¹⁶⁾ and angiotensin III ⁽¹⁵⁾. Its endopeptidase activity has been implicated in the metabolism of neurotensin ⁽¹⁷⁾. Cystine aminopaptidase (CysAP) hydrolyzes oxitocin and vasopresin ⁽¹⁸⁾. Due to these enzymes modulate the peptide neurotransmission ⁽¹⁰⁾, in the present work we have determinated the activity of several aminopeptidases (AlaAP, ArgAP, CysAP, LeuAP and TyrAP) in synaptosomes obtained from the frontal cortex of mouse, in basal and depolarized conditions, in presence of ethanol (25, 50 and 100 mM), and its relation to neurotoxic and metabolic effects of ethanol.

Discussion Board

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[ABSTRACT] [INTRODUCTION] [MATERIAL & METHODS] [RESULTS] [IMAGES] [IMAGES-2] [DISCUSSION] [BIBLIOGRAPHY] [Discussion Board]

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	[Neuroscience]	[Physiology]

María Dolores Mayas-Torres, José Manuel Martínez-Martos, María Jesús Ramírez-Expósito, María Jesús García-López, Isabel Prieto-Gómez, Garbiñe Arechaga-Maza, Manuel Ramírez-Sánchez
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Last update: 15/01/00