Septin-mediated RhoA activation engages the exocyst complex to recruit the cilium transition zone

Septins are filamentous GTPases that play important but poorly characterized roles in ciliogenesis. Here, we show that SEPTIN9 regulates RhoA signaling at the base of cilia by binding and activating the RhoA guanine nucleotide exchange factor, ARHGEF18. GTP-RhoA is known to activate the membrane targeting exocyst complex, and suppression of SEPTIN9 causes disruption of ciliogenesis and mislocalization of an exocyst subunit, SEC8. Using basal body-targeted proteins, we show that upregulating RhoA signaling at the cilium can rescue ciliary defects and mislocalization of SEC8 caused by global SEPTIN9 depletion. Moreover, we demonstrate that the transition zone components, RPGRIP1L and TCTN2, fail to accumulate at the transition zone in cells lacking SEPTIN9 or depleted of the exocyst complex. Thus, SEPTIN9 regulates the recruitment of transition zone proteins on Golgi-derived vesicles by activating the exocyst via RhoA to allow the formation of primary cilia.

Monoamine oxidase inhibitors: clinical review

Monoamine oxidase inhibitors (MAOIs) are effective antidepressant agents. They are increasingly and effectively used in a number of other psychiatric and non-psychiatric medical syndromes. Their potential for serious toxicity (i.e., hypertensive reaction) is far less than original reports suggest, and newer reversible substrate-specific MAOIs may offer even less toxicity. The author reviews the pharmacology, mechanism of action, clinical indications, and dosing strategies of MAOIs. The common MAOI side-effects (hypotension, weight gain, sexual dysfunction, insomnia, daytime sedation, myoclonus, and hypertensive episodes) are described and management techniques suggested. Recent clinical developments involving MAOIs are outlined.

Unnecessary delay in tricyclic antidepressant treatment of a patient with atrial fibrillation

Atrial fibrillation and other cardiac conduction disturbances are not contraindications for the use of tricyclic antidepressants. A case in which physician unfamiliarity with these facts led to an unnecessary delay in the antidepressant treatment of a patient with depression and long-standing atrial fibrillation is presented.

Common side effects associated with monoamine oxidase inhibitors

There is relatively little documentation on the common side effects associated with monoamine oxidase inhibitors (MAOI) and their frequency of occurrence. A retrospective chart review of patient records in a Mood Disorders Service was completed. Side effects of patients receiving phenelzine (N = 42) and tranylcypromine (N = 19) were rated as mild (resulting in no change in treatment), moderate (some modification in treatment plan necessary), and severe (definite change in treatment plan or drug discontinuation due to MAOI side effect). A total of 35 reports of side effects were noted in 15 of 19 tranylcypromine patients (1.84 per patients) and a total of 125 side effect reports were noted in 39 of 42 phenelzine patients (2.98 per patient). Only two severe tranylcypromine side effects occurred (resulting in drug cessation for one of these patients - hypotension), while 9 severe reactions occurred with phenelzine, resulting in drug discontinuation in 6 of these patients. The side effects for tranylcypromine and the number of reports were insomnia (N = 10), sedation (N = 8), hypotension (N = 5), sexual dysfunction (N = 3), hypomania (N = 3), weight gain/edema (N = 2), hypertensive episode (N = 2), and myoclonic jerking (N = 2). The number of reports of phenelzine side effects were insomnia (N = 26), hypomania/mania (N = 27; most common reason for drug cessation - 4), hypotension (N = 16; three cases considered severe), weight gain/edema (N = 15), sedation (N = 15), sexual dysfunction (N = 13), hypertensive episode (N = 6), and myoclonic jerking (N = 7).(ABSTRACT TRUNCATED AT 250 WORDS)