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Titolo:
Effects of acute tryptophan depletion on prepulse inhibition of the acoustic startle (eyeblink) response and the N1/P2 auditory evoked response in man
Autore:
Phillips, MA; Oxtoby, EK; Langley, RW; Bradshaw, CM; Szabadi, E;
Indirizzi:
Univ Nottingham, Div Psychiat, Psychopharmacol Sect, Sch Med,Queens Med Ctr, Nottingham NG7 2UH, England Univ Nottingham Nottingham England NG7 2UH, Nottingham NG7 2UH, England
Titolo Testata:
JOURNAL OF PSYCHOPHARMACOLOGY
fascicolo: 3, volume: 14, anno: 2000,
pagine: 258 - 265
SICI:
0269-8811(200009)14:3<258:EOATDO>2.0.ZU;2-S
Fonte:
ISI
Lingua:
ENG
Soggetto:
ANTIDEPRESSANT ACTION; HEALTHY-SUBJECTS; GATING DEFICITS; 5-HT MODULATION; D-AMPHETAMINE; WISTAR RATS; SCHIZOPHRENIA; HALOPERIDOL; REFLEX; VOLUNTEERS;
Keywords:
acoustic startle response; acute tryptophan depletion; auditory evoked potential; eyeblink; N1/P2 complex; prepulse inhibition;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
49
Recensione:
Indirizzi per estratti:
Indirizzo: Bradshaw, CM Univ Nottingham, Div Psychiat, Psychopharmacol Sect, Sch Med,Queens Med Ctr, Room B109, Nottingham NG7 2UH, England Univ Nottingham RoomB109 Nottingham England NG7 2UH England
Citazione:
M.A. Phillips et al., "Effects of acute tryptophan depletion on prepulse inhibition of the acoustic startle (eyeblink) response and the N1/P2 auditory evoked response in man", J PSYCHOPH, 14(3), 2000, pp. 258-265

Abstract

Contraction of the orbicularis oculi muscle in response to a sudden loud sound (acoustic startle response) and the N1/P2 component of the auditory evoked potential are both attenuated when a brief low-intensity stimulus is presented 30-500 ms before the 'startle-eliciting' stimulus (prepulse inhibition). Here, we report the effect of acute tryptophan depletion on prepulseinhibition of these responses. Thirteen males (21-52 years) participated in two sessions separated by 7 days, in which they ingested a drink containing a mixture of amino-acids, which either included (+ TP) or did not include (- TP) tryptophan, according to a balanced double-blind design. Electromyographic (EMG) responses of the orbicularis oculi muscle and N1/P2 auditoryevoked potentials were recorded in a 20-min session, 6 h after ingestion of the mixture. Subjects received 40 trials in which 1-kHz sounds were presented: (i) 40 ms, 115 dB ('pulse alone' trials) and (ii) 40 ms, 85 dB, followed after 120 ms by 40 ms, 115 dB ('prepulse/pulse' trials). Mean amplitudes of the EMG response and the N1/P2 potential were derived from the pulse-alone trials and, in each case, percentage prepulse inhibition was calculated. Plasma tryptophan levels were measured from blood samples taken before and 7 h after each treatment. Under the + TP condition, both the EMG response and the N1/P2 complex showed > 60% prepulse inhibition. The - TP condition was associated with (i) significant suppression of prepulse inhibition ofthe EMG response, with no significant change in response amplitude and (ii) reduction of the amplitude of the N1/P2 potential, with no significant change in prepulse inhibition of this response. Tryptophan levels rose by 90 /- 15% under the + TP condition and fell by 81 +/- 3% under the - TP condition. The suppression of prepulse inhibition of the acoustic startle response under the - TP condition suggests that central 5-hydroxytryptaminergic mechanisms may be involved in regulating prepulse inhibition of this response. The lack of effect of tryptophan depletion on prepulse inhibition of theN1/P2 potential suggests that different mechanisms are involved in prepulse inhibition of the startle response and the N1/P2 complex.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 27/01/20 alle ore 01:15:20