Sympatholytic effect of tricyclic antidepressants: site and mechanism of action in anesthetized rats.

Intravenous desipramine (DMI) and amitriptyline, but not fluoxetine, dose dependently inhibited splanchnic sympathetic nerve discharge (sSND; -64 +/- 3% after 4 mg/kg iv DMI, 172 ng/ml plasma) in urethan-anesthetized debuffered rats. Inhibition was reversed or prevented by microinjection of the alpha 2-adrenergic receptor (alpha 2-AR) antagonist 2-methoxyidazoxan (MOI) into the rostral ventrolateral medulla (RVLM, 1 nmol/side). sSND inhibition (-58 +/- 12%) by baclofen (8 mg/kg iv, a gamma-aminobutyric acid-B receptor agonist) was unaffected by MOI. MOI alone raised sSND 46 +/- 9%. Microinjection of 6-hydroxydopamine into the RVLM (2 micrograms/side, 10-13 days, to destroy noradrenergic terminals) did not change the effect of intravenous DMI or MOI on sSND. Slow-firing presympathetic neurons of the RVLM were activated by iontophoretic MOI (26 +/- 4%) and inhibited by 4 mg/kg iv DMI (-44 +/- 12%, effect reversed by alpha 2-AR antagonists iv). We interpret these findings as follows: 1) alpha 2-ARs in the RVLM are activated at rest, probably by catecholamines released by C1 adrenergic cells, 2) this activation reduces sSND, 3) DMI and amitriptyline reduce sSND by increasing alpha 2-AR activation in the RVLM, and 4) these effects are due to neither serotonin uptake inhibition nor blockade of norepinephrine uptake by noradrenergic fibers.

Clinical responses of A and B practising psychotherapists to schizoid and neurotic patient prototypes.

Eighty-three male psychotherapists varying on A-B type and experience orally responded to tape-recordings of simulated schizoid and neurotic patients in the privacy of their own offices. Five dimensions of therapist response were studied: accurate empathy, positive social-emotional reactions, negative social-emotional reactions, length of response and proportion of declarative statements. Although the simple A-B interaction effect was not found, significant second-order interactions were found for both accurate empathy and positive reactions which indicated that the predicted interaction effect tends to be upheld for inexperienced therapists but attenuated or reversed for experienced therapists. A significantly reversed interaction for experienced therapists' response length was also found. Examination of the results from this study and previous studies suggested a revision of the A-B interaction hypothesis: for inexperienced therapists, As will be more effective with schizoids/schizophrenics than Bs, whereas Bs will surpass As with neurotics; for experienced therapists, however, this interaction will be attenuated or reversed. Speculations about underlying processes in A-B interaction phenomena were offered.